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0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /* GTP according to GSM TS 09.60 / 3GPP TS 29.060
0003  *
0004  * (C) 2012-2014 by sysmocom - s.f.m.c. GmbH
0005  * (C) 2016 by Pablo Neira Ayuso <pablo@netfilter.org>
0006  *
0007  * Author: Harald Welte <hwelte@sysmocom.de>
0008  *     Pablo Neira Ayuso <pablo@netfilter.org>
0009  *     Andreas Schultz <aschultz@travelping.com>
0010  */
0011 
0012 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
0013 
0014 #include <linux/module.h>
0015 #include <linux/skbuff.h>
0016 #include <linux/udp.h>
0017 #include <linux/rculist.h>
0018 #include <linux/jhash.h>
0019 #include <linux/if_tunnel.h>
0020 #include <linux/net.h>
0021 #include <linux/file.h>
0022 #include <linux/gtp.h>
0023 
0024 #include <net/net_namespace.h>
0025 #include <net/protocol.h>
0026 #include <net/ip.h>
0027 #include <net/udp.h>
0028 #include <net/udp_tunnel.h>
0029 #include <net/icmp.h>
0030 #include <net/xfrm.h>
0031 #include <net/genetlink.h>
0032 #include <net/netns/generic.h>
0033 #include <net/gtp.h>
0034 
0035 /* An active session for the subscriber. */
0036 struct pdp_ctx {
0037     struct hlist_node   hlist_tid;
0038     struct hlist_node   hlist_addr;
0039 
0040     union {
0041         struct {
0042             u64 tid;
0043             u16 flow;
0044         } v0;
0045         struct {
0046             u32 i_tei;
0047             u32 o_tei;
0048         } v1;
0049     } u;
0050     u8          gtp_version;
0051     u16         af;
0052 
0053     struct in_addr      ms_addr_ip4;
0054     struct in_addr      peer_addr_ip4;
0055 
0056     struct sock     *sk;
0057     struct net_device       *dev;
0058 
0059     atomic_t        tx_seq;
0060     struct rcu_head     rcu_head;
0061 };
0062 
0063 /* One instance of the GTP device. */
0064 struct gtp_dev {
0065     struct list_head    list;
0066 
0067     struct sock     *sk0;
0068     struct sock     *sk1u;
0069     u8          sk_created;
0070 
0071     struct net_device   *dev;
0072     struct net      *net;
0073 
0074     unsigned int        role;
0075     unsigned int        hash_size;
0076     struct hlist_head   *tid_hash;
0077     struct hlist_head   *addr_hash;
0078 
0079     u8          restart_count;
0080 };
0081 
0082 struct echo_info {
0083     struct in_addr      ms_addr_ip4;
0084     struct in_addr      peer_addr_ip4;
0085     u8          gtp_version;
0086 };
0087 
0088 static unsigned int gtp_net_id __read_mostly;
0089 
0090 struct gtp_net {
0091     struct list_head gtp_dev_list;
0092 };
0093 
0094 static u32 gtp_h_initval;
0095 
0096 static struct genl_family gtp_genl_family;
0097 
0098 enum gtp_multicast_groups {
0099     GTP_GENL_MCGRP,
0100 };
0101 
0102 static const struct genl_multicast_group gtp_genl_mcgrps[] = {
0103     [GTP_GENL_MCGRP] = { .name = GTP_GENL_MCGRP_NAME },
0104 };
0105 
0106 static void pdp_context_delete(struct pdp_ctx *pctx);
0107 
0108 static inline u32 gtp0_hashfn(u64 tid)
0109 {
0110     u32 *tid32 = (u32 *) &tid;
0111     return jhash_2words(tid32[0], tid32[1], gtp_h_initval);
0112 }
0113 
0114 static inline u32 gtp1u_hashfn(u32 tid)
0115 {
0116     return jhash_1word(tid, gtp_h_initval);
0117 }
0118 
0119 static inline u32 ipv4_hashfn(__be32 ip)
0120 {
0121     return jhash_1word((__force u32)ip, gtp_h_initval);
0122 }
0123 
0124 /* Resolve a PDP context structure based on the 64bit TID. */
0125 static struct pdp_ctx *gtp0_pdp_find(struct gtp_dev *gtp, u64 tid)
0126 {
0127     struct hlist_head *head;
0128     struct pdp_ctx *pdp;
0129 
0130     head = &gtp->tid_hash[gtp0_hashfn(tid) % gtp->hash_size];
0131 
0132     hlist_for_each_entry_rcu(pdp, head, hlist_tid) {
0133         if (pdp->gtp_version == GTP_V0 &&
0134             pdp->u.v0.tid == tid)
0135             return pdp;
0136     }
0137     return NULL;
0138 }
0139 
0140 /* Resolve a PDP context structure based on the 32bit TEI. */
0141 static struct pdp_ctx *gtp1_pdp_find(struct gtp_dev *gtp, u32 tid)
0142 {
0143     struct hlist_head *head;
0144     struct pdp_ctx *pdp;
0145 
0146     head = &gtp->tid_hash[gtp1u_hashfn(tid) % gtp->hash_size];
0147 
0148     hlist_for_each_entry_rcu(pdp, head, hlist_tid) {
0149         if (pdp->gtp_version == GTP_V1 &&
0150             pdp->u.v1.i_tei == tid)
0151             return pdp;
0152     }
0153     return NULL;
0154 }
0155 
0156 /* Resolve a PDP context based on IPv4 address of MS. */
0157 static struct pdp_ctx *ipv4_pdp_find(struct gtp_dev *gtp, __be32 ms_addr)
0158 {
0159     struct hlist_head *head;
0160     struct pdp_ctx *pdp;
0161 
0162     head = &gtp->addr_hash[ipv4_hashfn(ms_addr) % gtp->hash_size];
0163 
0164     hlist_for_each_entry_rcu(pdp, head, hlist_addr) {
0165         if (pdp->af == AF_INET &&
0166             pdp->ms_addr_ip4.s_addr == ms_addr)
0167             return pdp;
0168     }
0169 
0170     return NULL;
0171 }
0172 
0173 static bool gtp_check_ms_ipv4(struct sk_buff *skb, struct pdp_ctx *pctx,
0174                   unsigned int hdrlen, unsigned int role)
0175 {
0176     struct iphdr *iph;
0177 
0178     if (!pskb_may_pull(skb, hdrlen + sizeof(struct iphdr)))
0179         return false;
0180 
0181     iph = (struct iphdr *)(skb->data + hdrlen);
0182 
0183     if (role == GTP_ROLE_SGSN)
0184         return iph->daddr == pctx->ms_addr_ip4.s_addr;
0185     else
0186         return iph->saddr == pctx->ms_addr_ip4.s_addr;
0187 }
0188 
0189 /* Check if the inner IP address in this packet is assigned to any
0190  * existing mobile subscriber.
0191  */
0192 static bool gtp_check_ms(struct sk_buff *skb, struct pdp_ctx *pctx,
0193                  unsigned int hdrlen, unsigned int role)
0194 {
0195     switch (ntohs(skb->protocol)) {
0196     case ETH_P_IP:
0197         return gtp_check_ms_ipv4(skb, pctx, hdrlen, role);
0198     }
0199     return false;
0200 }
0201 
0202 static int gtp_rx(struct pdp_ctx *pctx, struct sk_buff *skb,
0203             unsigned int hdrlen, unsigned int role)
0204 {
0205     if (!gtp_check_ms(skb, pctx, hdrlen, role)) {
0206         netdev_dbg(pctx->dev, "No PDP ctx for this MS\n");
0207         return 1;
0208     }
0209 
0210     /* Get rid of the GTP + UDP headers. */
0211     if (iptunnel_pull_header(skb, hdrlen, skb->protocol,
0212              !net_eq(sock_net(pctx->sk), dev_net(pctx->dev)))) {
0213         pctx->dev->stats.rx_length_errors++;
0214         goto err;
0215     }
0216 
0217     netdev_dbg(pctx->dev, "forwarding packet from GGSN to uplink\n");
0218 
0219     /* Now that the UDP and the GTP header have been removed, set up the
0220      * new network header. This is required by the upper layer to
0221      * calculate the transport header.
0222      */
0223     skb_reset_network_header(skb);
0224     skb_reset_mac_header(skb);
0225 
0226     skb->dev = pctx->dev;
0227 
0228     dev_sw_netstats_rx_add(pctx->dev, skb->len);
0229 
0230     __netif_rx(skb);
0231     return 0;
0232 
0233 err:
0234     pctx->dev->stats.rx_dropped++;
0235     return -1;
0236 }
0237 
0238 static struct rtable *ip4_route_output_gtp(struct flowi4 *fl4,
0239                        const struct sock *sk,
0240                        __be32 daddr, __be32 saddr)
0241 {
0242     memset(fl4, 0, sizeof(*fl4));
0243     fl4->flowi4_oif     = sk->sk_bound_dev_if;
0244     fl4->daddr      = daddr;
0245     fl4->saddr      = saddr;
0246     fl4->flowi4_tos     = RT_CONN_FLAGS(sk);
0247     fl4->flowi4_proto   = sk->sk_protocol;
0248 
0249     return ip_route_output_key(sock_net(sk), fl4);
0250 }
0251 
0252 /* GSM TS 09.60. 7.3
0253  * In all Path Management messages:
0254  * - TID: is not used and shall be set to 0.
0255  * - Flow Label is not used and shall be set to 0
0256  * In signalling messages:
0257  * - number: this field is not yet used in signalling messages.
0258  *   It shall be set to 255 by the sender and shall be ignored
0259  *   by the receiver
0260  * Returns true if the echo req was correct, false otherwise.
0261  */
0262 static bool gtp0_validate_echo_hdr(struct gtp0_header *gtp0)
0263 {
0264     return !(gtp0->tid || (gtp0->flags ^ 0x1e) ||
0265         gtp0->number != 0xff || gtp0->flow);
0266 }
0267 
0268 /* msg_type has to be GTP_ECHO_REQ or GTP_ECHO_RSP */
0269 static void gtp0_build_echo_msg(struct gtp0_header *hdr, __u8 msg_type)
0270 {
0271     int len_pkt, len_hdr;
0272 
0273     hdr->flags = 0x1e; /* v0, GTP-non-prime. */
0274     hdr->type = msg_type;
0275     /* GSM TS 09.60. 7.3 In all Path Management Flow Label and TID
0276      * are not used and shall be set to 0.
0277      */
0278     hdr->flow = 0;
0279     hdr->tid = 0;
0280     hdr->number = 0xff;
0281     hdr->spare[0] = 0xff;
0282     hdr->spare[1] = 0xff;
0283     hdr->spare[2] = 0xff;
0284 
0285     len_pkt = sizeof(struct gtp0_packet);
0286     len_hdr = sizeof(struct gtp0_header);
0287 
0288     if (msg_type == GTP_ECHO_RSP)
0289         hdr->length = htons(len_pkt - len_hdr);
0290     else
0291         hdr->length = 0;
0292 }
0293 
0294 static int gtp0_send_echo_resp(struct gtp_dev *gtp, struct sk_buff *skb)
0295 {
0296     struct gtp0_packet *gtp_pkt;
0297     struct gtp0_header *gtp0;
0298     struct rtable *rt;
0299     struct flowi4 fl4;
0300     struct iphdr *iph;
0301     __be16 seq;
0302 
0303     gtp0 = (struct gtp0_header *)(skb->data + sizeof(struct udphdr));
0304 
0305     if (!gtp0_validate_echo_hdr(gtp0))
0306         return -1;
0307 
0308     seq = gtp0->seq;
0309 
0310     /* pull GTP and UDP headers */
0311     skb_pull_data(skb, sizeof(struct gtp0_header) + sizeof(struct udphdr));
0312 
0313     gtp_pkt = skb_push(skb, sizeof(struct gtp0_packet));
0314     memset(gtp_pkt, 0, sizeof(struct gtp0_packet));
0315 
0316     gtp0_build_echo_msg(&gtp_pkt->gtp0_h, GTP_ECHO_RSP);
0317 
0318     /* GSM TS 09.60. 7.3 The Sequence Number in a signalling response
0319      * message shall be copied from the signalling request message
0320      * that the GSN is replying to.
0321      */
0322     gtp_pkt->gtp0_h.seq = seq;
0323 
0324     gtp_pkt->ie.tag = GTPIE_RECOVERY;
0325     gtp_pkt->ie.val = gtp->restart_count;
0326 
0327     iph = ip_hdr(skb);
0328 
0329     /* find route to the sender,
0330      * src address becomes dst address and vice versa.
0331      */
0332     rt = ip4_route_output_gtp(&fl4, gtp->sk0, iph->saddr, iph->daddr);
0333     if (IS_ERR(rt)) {
0334         netdev_dbg(gtp->dev, "no route for echo response from %pI4\n",
0335                &iph->saddr);
0336         return -1;
0337     }
0338 
0339     udp_tunnel_xmit_skb(rt, gtp->sk0, skb,
0340                 fl4.saddr, fl4.daddr,
0341                 iph->tos,
0342                 ip4_dst_hoplimit(&rt->dst),
0343                 0,
0344                 htons(GTP0_PORT), htons(GTP0_PORT),
0345                 !net_eq(sock_net(gtp->sk1u),
0346                     dev_net(gtp->dev)),
0347                 false);
0348     return 0;
0349 }
0350 
0351 static int gtp_genl_fill_echo(struct sk_buff *skb, u32 snd_portid, u32 snd_seq,
0352                   int flags, u32 type, struct echo_info echo)
0353 {
0354     void *genlh;
0355 
0356     genlh = genlmsg_put(skb, snd_portid, snd_seq, &gtp_genl_family, flags,
0357                 type);
0358     if (!genlh)
0359         goto failure;
0360 
0361     if (nla_put_u32(skb, GTPA_VERSION, echo.gtp_version) ||
0362         nla_put_be32(skb, GTPA_PEER_ADDRESS, echo.peer_addr_ip4.s_addr) ||
0363         nla_put_be32(skb, GTPA_MS_ADDRESS, echo.ms_addr_ip4.s_addr))
0364         goto failure;
0365 
0366     genlmsg_end(skb, genlh);
0367     return 0;
0368 
0369 failure:
0370     genlmsg_cancel(skb, genlh);
0371     return -EMSGSIZE;
0372 }
0373 
0374 static int gtp0_handle_echo_resp(struct gtp_dev *gtp, struct sk_buff *skb)
0375 {
0376     struct gtp0_header *gtp0;
0377     struct echo_info echo;
0378     struct sk_buff *msg;
0379     struct iphdr *iph;
0380     int ret;
0381 
0382     gtp0 = (struct gtp0_header *)(skb->data + sizeof(struct udphdr));
0383 
0384     if (!gtp0_validate_echo_hdr(gtp0))
0385         return -1;
0386 
0387     iph = ip_hdr(skb);
0388     echo.ms_addr_ip4.s_addr = iph->daddr;
0389     echo.peer_addr_ip4.s_addr = iph->saddr;
0390     echo.gtp_version = GTP_V0;
0391 
0392     msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
0393     if (!msg)
0394         return -ENOMEM;
0395 
0396     ret = gtp_genl_fill_echo(msg, 0, 0, 0, GTP_CMD_ECHOREQ, echo);
0397     if (ret < 0) {
0398         nlmsg_free(msg);
0399         return ret;
0400     }
0401 
0402     return genlmsg_multicast_netns(&gtp_genl_family, dev_net(gtp->dev),
0403                        msg, 0, GTP_GENL_MCGRP, GFP_ATOMIC);
0404 }
0405 
0406 /* 1 means pass up to the stack, -1 means drop and 0 means decapsulated. */
0407 static int gtp0_udp_encap_recv(struct gtp_dev *gtp, struct sk_buff *skb)
0408 {
0409     unsigned int hdrlen = sizeof(struct udphdr) +
0410                   sizeof(struct gtp0_header);
0411     struct gtp0_header *gtp0;
0412     struct pdp_ctx *pctx;
0413 
0414     if (!pskb_may_pull(skb, hdrlen))
0415         return -1;
0416 
0417     gtp0 = (struct gtp0_header *)(skb->data + sizeof(struct udphdr));
0418 
0419     if ((gtp0->flags >> 5) != GTP_V0)
0420         return 1;
0421 
0422     /* If the sockets were created in kernel, it means that
0423      * there is no daemon running in userspace which would
0424      * handle echo request.
0425      */
0426     if (gtp0->type == GTP_ECHO_REQ && gtp->sk_created)
0427         return gtp0_send_echo_resp(gtp, skb);
0428 
0429     if (gtp0->type == GTP_ECHO_RSP && gtp->sk_created)
0430         return gtp0_handle_echo_resp(gtp, skb);
0431 
0432     if (gtp0->type != GTP_TPDU)
0433         return 1;
0434 
0435     pctx = gtp0_pdp_find(gtp, be64_to_cpu(gtp0->tid));
0436     if (!pctx) {
0437         netdev_dbg(gtp->dev, "No PDP ctx to decap skb=%p\n", skb);
0438         return 1;
0439     }
0440 
0441     return gtp_rx(pctx, skb, hdrlen, gtp->role);
0442 }
0443 
0444 /* msg_type has to be GTP_ECHO_REQ or GTP_ECHO_RSP */
0445 static void gtp1u_build_echo_msg(struct gtp1_header_long *hdr, __u8 msg_type)
0446 {
0447     int len_pkt, len_hdr;
0448 
0449     /* S flag must be set to 1 */
0450     hdr->flags = 0x32; /* v1, GTP-non-prime. */
0451     hdr->type = msg_type;
0452     /* 3GPP TS 29.281 5.1 - TEID has to be set to 0 */
0453     hdr->tid = 0;
0454 
0455     /* seq, npdu and next should be counted to the length of the GTP packet
0456      * that's why szie of gtp1_header should be subtracted,
0457      * not size of gtp1_header_long.
0458      */
0459 
0460     len_hdr = sizeof(struct gtp1_header);
0461 
0462     if (msg_type == GTP_ECHO_RSP) {
0463         len_pkt = sizeof(struct gtp1u_packet);
0464         hdr->length = htons(len_pkt - len_hdr);
0465     } else {
0466         /* GTP_ECHO_REQ does not carry GTP Information Element,
0467          * the why gtp1_header_long is used here.
0468          */
0469         len_pkt = sizeof(struct gtp1_header_long);
0470         hdr->length = htons(len_pkt - len_hdr);
0471     }
0472 }
0473 
0474 static int gtp1u_send_echo_resp(struct gtp_dev *gtp, struct sk_buff *skb)
0475 {
0476     struct gtp1_header_long *gtp1u;
0477     struct gtp1u_packet *gtp_pkt;
0478     struct rtable *rt;
0479     struct flowi4 fl4;
0480     struct iphdr *iph;
0481 
0482     gtp1u = (struct gtp1_header_long *)(skb->data + sizeof(struct udphdr));
0483 
0484     /* 3GPP TS 29.281 5.1 - For the Echo Request, Echo Response,
0485      * Error Indication and Supported Extension Headers Notification
0486      * messages, the S flag shall be set to 1 and TEID shall be set to 0.
0487      */
0488     if (!(gtp1u->flags & GTP1_F_SEQ) || gtp1u->tid)
0489         return -1;
0490 
0491     /* pull GTP and UDP headers */
0492     skb_pull_data(skb,
0493               sizeof(struct gtp1_header_long) + sizeof(struct udphdr));
0494 
0495     gtp_pkt = skb_push(skb, sizeof(struct gtp1u_packet));
0496     memset(gtp_pkt, 0, sizeof(struct gtp1u_packet));
0497 
0498     gtp1u_build_echo_msg(&gtp_pkt->gtp1u_h, GTP_ECHO_RSP);
0499 
0500     /* 3GPP TS 29.281 7.7.2 - The Restart Counter value in the
0501      * Recovery information element shall not be used, i.e. it shall
0502      * be set to zero by the sender and shall be ignored by the receiver.
0503      * The Recovery information element is mandatory due to backwards
0504      * compatibility reasons.
0505      */
0506     gtp_pkt->ie.tag = GTPIE_RECOVERY;
0507     gtp_pkt->ie.val = 0;
0508 
0509     iph = ip_hdr(skb);
0510 
0511     /* find route to the sender,
0512      * src address becomes dst address and vice versa.
0513      */
0514     rt = ip4_route_output_gtp(&fl4, gtp->sk1u, iph->saddr, iph->daddr);
0515     if (IS_ERR(rt)) {
0516         netdev_dbg(gtp->dev, "no route for echo response from %pI4\n",
0517                &iph->saddr);
0518         return -1;
0519     }
0520 
0521     udp_tunnel_xmit_skb(rt, gtp->sk1u, skb,
0522                 fl4.saddr, fl4.daddr,
0523                 iph->tos,
0524                 ip4_dst_hoplimit(&rt->dst),
0525                 0,
0526                 htons(GTP1U_PORT), htons(GTP1U_PORT),
0527                 !net_eq(sock_net(gtp->sk1u),
0528                     dev_net(gtp->dev)),
0529                 false);
0530     return 0;
0531 }
0532 
0533 static int gtp1u_handle_echo_resp(struct gtp_dev *gtp, struct sk_buff *skb)
0534 {
0535     struct gtp1_header_long *gtp1u;
0536     struct echo_info echo;
0537     struct sk_buff *msg;
0538     struct iphdr *iph;
0539     int ret;
0540 
0541     gtp1u = (struct gtp1_header_long *)(skb->data + sizeof(struct udphdr));
0542 
0543     /* 3GPP TS 29.281 5.1 - For the Echo Request, Echo Response,
0544      * Error Indication and Supported Extension Headers Notification
0545      * messages, the S flag shall be set to 1 and TEID shall be set to 0.
0546      */
0547     if (!(gtp1u->flags & GTP1_F_SEQ) || gtp1u->tid)
0548         return -1;
0549 
0550     iph = ip_hdr(skb);
0551     echo.ms_addr_ip4.s_addr = iph->daddr;
0552     echo.peer_addr_ip4.s_addr = iph->saddr;
0553     echo.gtp_version = GTP_V1;
0554 
0555     msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
0556     if (!msg)
0557         return -ENOMEM;
0558 
0559     ret = gtp_genl_fill_echo(msg, 0, 0, 0, GTP_CMD_ECHOREQ, echo);
0560     if (ret < 0) {
0561         nlmsg_free(msg);
0562         return ret;
0563     }
0564 
0565     return genlmsg_multicast_netns(&gtp_genl_family, dev_net(gtp->dev),
0566                        msg, 0, GTP_GENL_MCGRP, GFP_ATOMIC);
0567 }
0568 
0569 static int gtp1u_udp_encap_recv(struct gtp_dev *gtp, struct sk_buff *skb)
0570 {
0571     unsigned int hdrlen = sizeof(struct udphdr) +
0572                   sizeof(struct gtp1_header);
0573     struct gtp1_header *gtp1;
0574     struct pdp_ctx *pctx;
0575 
0576     if (!pskb_may_pull(skb, hdrlen))
0577         return -1;
0578 
0579     gtp1 = (struct gtp1_header *)(skb->data + sizeof(struct udphdr));
0580 
0581     if ((gtp1->flags >> 5) != GTP_V1)
0582         return 1;
0583 
0584     /* If the sockets were created in kernel, it means that
0585      * there is no daemon running in userspace which would
0586      * handle echo request.
0587      */
0588     if (gtp1->type == GTP_ECHO_REQ && gtp->sk_created)
0589         return gtp1u_send_echo_resp(gtp, skb);
0590 
0591     if (gtp1->type == GTP_ECHO_RSP && gtp->sk_created)
0592         return gtp1u_handle_echo_resp(gtp, skb);
0593 
0594     if (gtp1->type != GTP_TPDU)
0595         return 1;
0596 
0597     /* From 29.060: "This field shall be present if and only if any one or
0598      * more of the S, PN and E flags are set.".
0599      *
0600      * If any of the bit is set, then the remaining ones also have to be
0601      * set.
0602      */
0603     if (gtp1->flags & GTP1_F_MASK)
0604         hdrlen += 4;
0605 
0606     /* Make sure the header is larger enough, including extensions. */
0607     if (!pskb_may_pull(skb, hdrlen))
0608         return -1;
0609 
0610     gtp1 = (struct gtp1_header *)(skb->data + sizeof(struct udphdr));
0611 
0612     pctx = gtp1_pdp_find(gtp, ntohl(gtp1->tid));
0613     if (!pctx) {
0614         netdev_dbg(gtp->dev, "No PDP ctx to decap skb=%p\n", skb);
0615         return 1;
0616     }
0617 
0618     return gtp_rx(pctx, skb, hdrlen, gtp->role);
0619 }
0620 
0621 static void __gtp_encap_destroy(struct sock *sk)
0622 {
0623     struct gtp_dev *gtp;
0624 
0625     lock_sock(sk);
0626     gtp = sk->sk_user_data;
0627     if (gtp) {
0628         if (gtp->sk0 == sk)
0629             gtp->sk0 = NULL;
0630         else
0631             gtp->sk1u = NULL;
0632         udp_sk(sk)->encap_type = 0;
0633         rcu_assign_sk_user_data(sk, NULL);
0634         sock_put(sk);
0635     }
0636     release_sock(sk);
0637 }
0638 
0639 static void gtp_encap_destroy(struct sock *sk)
0640 {
0641     rtnl_lock();
0642     __gtp_encap_destroy(sk);
0643     rtnl_unlock();
0644 }
0645 
0646 static void gtp_encap_disable_sock(struct sock *sk)
0647 {
0648     if (!sk)
0649         return;
0650 
0651     __gtp_encap_destroy(sk);
0652 }
0653 
0654 static void gtp_encap_disable(struct gtp_dev *gtp)
0655 {
0656     if (gtp->sk_created) {
0657         udp_tunnel_sock_release(gtp->sk0->sk_socket);
0658         udp_tunnel_sock_release(gtp->sk1u->sk_socket);
0659         gtp->sk_created = false;
0660         gtp->sk0 = NULL;
0661         gtp->sk1u = NULL;
0662     } else {
0663         gtp_encap_disable_sock(gtp->sk0);
0664         gtp_encap_disable_sock(gtp->sk1u);
0665     }
0666 }
0667 
0668 /* UDP encapsulation receive handler. See net/ipv4/udp.c.
0669  * Return codes: 0: success, <0: error, >0: pass up to userspace UDP socket.
0670  */
0671 static int gtp_encap_recv(struct sock *sk, struct sk_buff *skb)
0672 {
0673     struct gtp_dev *gtp;
0674     int ret = 0;
0675 
0676     gtp = rcu_dereference_sk_user_data(sk);
0677     if (!gtp)
0678         return 1;
0679 
0680     netdev_dbg(gtp->dev, "encap_recv sk=%p\n", sk);
0681 
0682     switch (udp_sk(sk)->encap_type) {
0683     case UDP_ENCAP_GTP0:
0684         netdev_dbg(gtp->dev, "received GTP0 packet\n");
0685         ret = gtp0_udp_encap_recv(gtp, skb);
0686         break;
0687     case UDP_ENCAP_GTP1U:
0688         netdev_dbg(gtp->dev, "received GTP1U packet\n");
0689         ret = gtp1u_udp_encap_recv(gtp, skb);
0690         break;
0691     default:
0692         ret = -1; /* Shouldn't happen. */
0693     }
0694 
0695     switch (ret) {
0696     case 1:
0697         netdev_dbg(gtp->dev, "pass up to the process\n");
0698         break;
0699     case 0:
0700         break;
0701     case -1:
0702         netdev_dbg(gtp->dev, "GTP packet has been dropped\n");
0703         kfree_skb(skb);
0704         ret = 0;
0705         break;
0706     }
0707 
0708     return ret;
0709 }
0710 
0711 static int gtp_dev_init(struct net_device *dev)
0712 {
0713     struct gtp_dev *gtp = netdev_priv(dev);
0714 
0715     gtp->dev = dev;
0716 
0717     dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
0718     if (!dev->tstats)
0719         return -ENOMEM;
0720 
0721     return 0;
0722 }
0723 
0724 static void gtp_dev_uninit(struct net_device *dev)
0725 {
0726     struct gtp_dev *gtp = netdev_priv(dev);
0727 
0728     gtp_encap_disable(gtp);
0729     free_percpu(dev->tstats);
0730 }
0731 
0732 static inline void gtp0_push_header(struct sk_buff *skb, struct pdp_ctx *pctx)
0733 {
0734     int payload_len = skb->len;
0735     struct gtp0_header *gtp0;
0736 
0737     gtp0 = skb_push(skb, sizeof(*gtp0));
0738 
0739     gtp0->flags = 0x1e; /* v0, GTP-non-prime. */
0740     gtp0->type  = GTP_TPDU;
0741     gtp0->length    = htons(payload_len);
0742     gtp0->seq   = htons((atomic_inc_return(&pctx->tx_seq) - 1) % 0xffff);
0743     gtp0->flow  = htons(pctx->u.v0.flow);
0744     gtp0->number    = 0xff;
0745     gtp0->spare[0]  = gtp0->spare[1] = gtp0->spare[2] = 0xff;
0746     gtp0->tid   = cpu_to_be64(pctx->u.v0.tid);
0747 }
0748 
0749 static inline void gtp1_push_header(struct sk_buff *skb, struct pdp_ctx *pctx)
0750 {
0751     int payload_len = skb->len;
0752     struct gtp1_header *gtp1;
0753 
0754     gtp1 = skb_push(skb, sizeof(*gtp1));
0755 
0756     /* Bits    8  7  6  5  4  3  2  1
0757      *    +--+--+--+--+--+--+--+--+
0758      *    |version |PT| 0| E| S|PN|
0759      *    +--+--+--+--+--+--+--+--+
0760      *      0  0  1  1  1  0  0  0
0761      */
0762     gtp1->flags = 0x30; /* v1, GTP-non-prime. */
0763     gtp1->type  = GTP_TPDU;
0764     gtp1->length    = htons(payload_len);
0765     gtp1->tid   = htonl(pctx->u.v1.o_tei);
0766 
0767     /* TODO: Support for extension header, sequence number and N-PDU.
0768      *   Update the length field if any of them is available.
0769      */
0770 }
0771 
0772 struct gtp_pktinfo {
0773     struct sock     *sk;
0774     struct iphdr        *iph;
0775     struct flowi4       fl4;
0776     struct rtable       *rt;
0777     struct pdp_ctx      *pctx;
0778     struct net_device   *dev;
0779     __be16          gtph_port;
0780 };
0781 
0782 static void gtp_push_header(struct sk_buff *skb, struct gtp_pktinfo *pktinfo)
0783 {
0784     switch (pktinfo->pctx->gtp_version) {
0785     case GTP_V0:
0786         pktinfo->gtph_port = htons(GTP0_PORT);
0787         gtp0_push_header(skb, pktinfo->pctx);
0788         break;
0789     case GTP_V1:
0790         pktinfo->gtph_port = htons(GTP1U_PORT);
0791         gtp1_push_header(skb, pktinfo->pctx);
0792         break;
0793     }
0794 }
0795 
0796 static inline void gtp_set_pktinfo_ipv4(struct gtp_pktinfo *pktinfo,
0797                     struct sock *sk, struct iphdr *iph,
0798                     struct pdp_ctx *pctx, struct rtable *rt,
0799                     struct flowi4 *fl4,
0800                     struct net_device *dev)
0801 {
0802     pktinfo->sk = sk;
0803     pktinfo->iph    = iph;
0804     pktinfo->pctx   = pctx;
0805     pktinfo->rt = rt;
0806     pktinfo->fl4    = *fl4;
0807     pktinfo->dev    = dev;
0808 }
0809 
0810 static int gtp_build_skb_ip4(struct sk_buff *skb, struct net_device *dev,
0811                  struct gtp_pktinfo *pktinfo)
0812 {
0813     struct gtp_dev *gtp = netdev_priv(dev);
0814     struct pdp_ctx *pctx;
0815     struct rtable *rt;
0816     struct flowi4 fl4;
0817     struct iphdr *iph;
0818     __be16 df;
0819     int mtu;
0820 
0821     /* Read the IP destination address and resolve the PDP context.
0822      * Prepend PDP header with TEI/TID from PDP ctx.
0823      */
0824     iph = ip_hdr(skb);
0825     if (gtp->role == GTP_ROLE_SGSN)
0826         pctx = ipv4_pdp_find(gtp, iph->saddr);
0827     else
0828         pctx = ipv4_pdp_find(gtp, iph->daddr);
0829 
0830     if (!pctx) {
0831         netdev_dbg(dev, "no PDP ctx found for %pI4, skip\n",
0832                &iph->daddr);
0833         return -ENOENT;
0834     }
0835     netdev_dbg(dev, "found PDP context %p\n", pctx);
0836 
0837     rt = ip4_route_output_gtp(&fl4, pctx->sk, pctx->peer_addr_ip4.s_addr,
0838                   inet_sk(pctx->sk)->inet_saddr);
0839     if (IS_ERR(rt)) {
0840         netdev_dbg(dev, "no route to SSGN %pI4\n",
0841                &pctx->peer_addr_ip4.s_addr);
0842         dev->stats.tx_carrier_errors++;
0843         goto err;
0844     }
0845 
0846     if (rt->dst.dev == dev) {
0847         netdev_dbg(dev, "circular route to SSGN %pI4\n",
0848                &pctx->peer_addr_ip4.s_addr);
0849         dev->stats.collisions++;
0850         goto err_rt;
0851     }
0852 
0853     /* This is similar to tnl_update_pmtu(). */
0854     df = iph->frag_off;
0855     if (df) {
0856         mtu = dst_mtu(&rt->dst) - dev->hard_header_len -
0857             sizeof(struct iphdr) - sizeof(struct udphdr);
0858         switch (pctx->gtp_version) {
0859         case GTP_V0:
0860             mtu -= sizeof(struct gtp0_header);
0861             break;
0862         case GTP_V1:
0863             mtu -= sizeof(struct gtp1_header);
0864             break;
0865         }
0866     } else {
0867         mtu = dst_mtu(&rt->dst);
0868     }
0869 
0870     skb_dst_update_pmtu_no_confirm(skb, mtu);
0871 
0872     if (!skb_is_gso(skb) && (iph->frag_off & htons(IP_DF)) &&
0873         mtu < ntohs(iph->tot_len)) {
0874         netdev_dbg(dev, "packet too big, fragmentation needed\n");
0875         icmp_ndo_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
0876                   htonl(mtu));
0877         goto err_rt;
0878     }
0879 
0880     gtp_set_pktinfo_ipv4(pktinfo, pctx->sk, iph, pctx, rt, &fl4, dev);
0881     gtp_push_header(skb, pktinfo);
0882 
0883     return 0;
0884 err_rt:
0885     ip_rt_put(rt);
0886 err:
0887     return -EBADMSG;
0888 }
0889 
0890 static netdev_tx_t gtp_dev_xmit(struct sk_buff *skb, struct net_device *dev)
0891 {
0892     unsigned int proto = ntohs(skb->protocol);
0893     struct gtp_pktinfo pktinfo;
0894     int err;
0895 
0896     /* Ensure there is sufficient headroom. */
0897     if (skb_cow_head(skb, dev->needed_headroom))
0898         goto tx_err;
0899 
0900     skb_reset_inner_headers(skb);
0901 
0902     /* PDP context lookups in gtp_build_skb_*() need rcu read-side lock. */
0903     rcu_read_lock();
0904     switch (proto) {
0905     case ETH_P_IP:
0906         err = gtp_build_skb_ip4(skb, dev, &pktinfo);
0907         break;
0908     default:
0909         err = -EOPNOTSUPP;
0910         break;
0911     }
0912     rcu_read_unlock();
0913 
0914     if (err < 0)
0915         goto tx_err;
0916 
0917     switch (proto) {
0918     case ETH_P_IP:
0919         netdev_dbg(pktinfo.dev, "gtp -> IP src: %pI4 dst: %pI4\n",
0920                &pktinfo.iph->saddr, &pktinfo.iph->daddr);
0921         udp_tunnel_xmit_skb(pktinfo.rt, pktinfo.sk, skb,
0922                     pktinfo.fl4.saddr, pktinfo.fl4.daddr,
0923                     pktinfo.iph->tos,
0924                     ip4_dst_hoplimit(&pktinfo.rt->dst),
0925                     0,
0926                     pktinfo.gtph_port, pktinfo.gtph_port,
0927                     !net_eq(sock_net(pktinfo.pctx->sk),
0928                         dev_net(dev)),
0929                     false);
0930         break;
0931     }
0932 
0933     return NETDEV_TX_OK;
0934 tx_err:
0935     dev->stats.tx_errors++;
0936     dev_kfree_skb(skb);
0937     return NETDEV_TX_OK;
0938 }
0939 
0940 static const struct net_device_ops gtp_netdev_ops = {
0941     .ndo_init       = gtp_dev_init,
0942     .ndo_uninit     = gtp_dev_uninit,
0943     .ndo_start_xmit     = gtp_dev_xmit,
0944     .ndo_get_stats64    = dev_get_tstats64,
0945 };
0946 
0947 static const struct device_type gtp_type = {
0948     .name = "gtp",
0949 };
0950 
0951 static void gtp_link_setup(struct net_device *dev)
0952 {
0953     unsigned int max_gtp_header_len = sizeof(struct iphdr) +
0954                       sizeof(struct udphdr) +
0955                       sizeof(struct gtp0_header);
0956 
0957     dev->netdev_ops     = &gtp_netdev_ops;
0958     dev->needs_free_netdev  = true;
0959     SET_NETDEV_DEVTYPE(dev, &gtp_type);
0960 
0961     dev->hard_header_len = 0;
0962     dev->addr_len = 0;
0963     dev->mtu = ETH_DATA_LEN - max_gtp_header_len;
0964 
0965     /* Zero header length. */
0966     dev->type = ARPHRD_NONE;
0967     dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
0968 
0969     dev->priv_flags |= IFF_NO_QUEUE;
0970     dev->features   |= NETIF_F_LLTX;
0971     netif_keep_dst(dev);
0972 
0973     dev->needed_headroom    = LL_MAX_HEADER + max_gtp_header_len;
0974 }
0975 
0976 static int gtp_hashtable_new(struct gtp_dev *gtp, int hsize);
0977 static int gtp_encap_enable(struct gtp_dev *gtp, struct nlattr *data[]);
0978 
0979 static void gtp_destructor(struct net_device *dev)
0980 {
0981     struct gtp_dev *gtp = netdev_priv(dev);
0982 
0983     kfree(gtp->addr_hash);
0984     kfree(gtp->tid_hash);
0985 }
0986 
0987 static struct sock *gtp_create_sock(int type, struct gtp_dev *gtp)
0988 {
0989     struct udp_tunnel_sock_cfg tuncfg = {};
0990     struct udp_port_cfg udp_conf = {
0991         .local_ip.s_addr    = htonl(INADDR_ANY),
0992         .family         = AF_INET,
0993     };
0994     struct net *net = gtp->net;
0995     struct socket *sock;
0996     int err;
0997 
0998     if (type == UDP_ENCAP_GTP0)
0999         udp_conf.local_udp_port = htons(GTP0_PORT);
1000     else if (type == UDP_ENCAP_GTP1U)
1001         udp_conf.local_udp_port = htons(GTP1U_PORT);
1002     else
1003         return ERR_PTR(-EINVAL);
1004 
1005     err = udp_sock_create(net, &udp_conf, &sock);
1006     if (err)
1007         return ERR_PTR(err);
1008 
1009     tuncfg.sk_user_data = gtp;
1010     tuncfg.encap_type = type;
1011     tuncfg.encap_rcv = gtp_encap_recv;
1012     tuncfg.encap_destroy = NULL;
1013 
1014     setup_udp_tunnel_sock(net, sock, &tuncfg);
1015 
1016     return sock->sk;
1017 }
1018 
1019 static int gtp_create_sockets(struct gtp_dev *gtp, struct nlattr *data[])
1020 {
1021     struct sock *sk1u = NULL;
1022     struct sock *sk0 = NULL;
1023 
1024     sk0 = gtp_create_sock(UDP_ENCAP_GTP0, gtp);
1025     if (IS_ERR(sk0))
1026         return PTR_ERR(sk0);
1027 
1028     sk1u = gtp_create_sock(UDP_ENCAP_GTP1U, gtp);
1029     if (IS_ERR(sk1u)) {
1030         udp_tunnel_sock_release(sk0->sk_socket);
1031         return PTR_ERR(sk1u);
1032     }
1033 
1034     gtp->sk_created = true;
1035     gtp->sk0 = sk0;
1036     gtp->sk1u = sk1u;
1037 
1038     return 0;
1039 }
1040 
1041 static int gtp_newlink(struct net *src_net, struct net_device *dev,
1042                struct nlattr *tb[], struct nlattr *data[],
1043                struct netlink_ext_ack *extack)
1044 {
1045     unsigned int role = GTP_ROLE_GGSN;
1046     struct gtp_dev *gtp;
1047     struct gtp_net *gn;
1048     int hashsize, err;
1049 
1050     gtp = netdev_priv(dev);
1051 
1052     if (!data[IFLA_GTP_PDP_HASHSIZE]) {
1053         hashsize = 1024;
1054     } else {
1055         hashsize = nla_get_u32(data[IFLA_GTP_PDP_HASHSIZE]);
1056         if (!hashsize)
1057             hashsize = 1024;
1058     }
1059 
1060     if (data[IFLA_GTP_ROLE]) {
1061         role = nla_get_u32(data[IFLA_GTP_ROLE]);
1062         if (role > GTP_ROLE_SGSN)
1063             return -EINVAL;
1064     }
1065     gtp->role = role;
1066 
1067     if (!data[IFLA_GTP_RESTART_COUNT])
1068         gtp->restart_count = 0;
1069     else
1070         gtp->restart_count = nla_get_u8(data[IFLA_GTP_RESTART_COUNT]);
1071 
1072     gtp->net = src_net;
1073 
1074     err = gtp_hashtable_new(gtp, hashsize);
1075     if (err < 0)
1076         return err;
1077 
1078     if (data[IFLA_GTP_CREATE_SOCKETS])
1079         err = gtp_create_sockets(gtp, data);
1080     else
1081         err = gtp_encap_enable(gtp, data);
1082     if (err < 0)
1083         goto out_hashtable;
1084 
1085     err = register_netdevice(dev);
1086     if (err < 0) {
1087         netdev_dbg(dev, "failed to register new netdev %d\n", err);
1088         goto out_encap;
1089     }
1090 
1091     gn = net_generic(dev_net(dev), gtp_net_id);
1092     list_add_rcu(&gtp->list, &gn->gtp_dev_list);
1093     dev->priv_destructor = gtp_destructor;
1094 
1095     netdev_dbg(dev, "registered new GTP interface\n");
1096 
1097     return 0;
1098 
1099 out_encap:
1100     gtp_encap_disable(gtp);
1101 out_hashtable:
1102     kfree(gtp->addr_hash);
1103     kfree(gtp->tid_hash);
1104     return err;
1105 }
1106 
1107 static void gtp_dellink(struct net_device *dev, struct list_head *head)
1108 {
1109     struct gtp_dev *gtp = netdev_priv(dev);
1110     struct pdp_ctx *pctx;
1111     int i;
1112 
1113     for (i = 0; i < gtp->hash_size; i++)
1114         hlist_for_each_entry_rcu(pctx, &gtp->tid_hash[i], hlist_tid)
1115             pdp_context_delete(pctx);
1116 
1117     list_del_rcu(&gtp->list);
1118     unregister_netdevice_queue(dev, head);
1119 }
1120 
1121 static const struct nla_policy gtp_policy[IFLA_GTP_MAX + 1] = {
1122     [IFLA_GTP_FD0]          = { .type = NLA_U32 },
1123     [IFLA_GTP_FD1]          = { .type = NLA_U32 },
1124     [IFLA_GTP_PDP_HASHSIZE]     = { .type = NLA_U32 },
1125     [IFLA_GTP_ROLE]         = { .type = NLA_U32 },
1126     [IFLA_GTP_CREATE_SOCKETS]   = { .type = NLA_U8 },
1127     [IFLA_GTP_RESTART_COUNT]    = { .type = NLA_U8 },
1128 };
1129 
1130 static int gtp_validate(struct nlattr *tb[], struct nlattr *data[],
1131             struct netlink_ext_ack *extack)
1132 {
1133     if (!data)
1134         return -EINVAL;
1135 
1136     return 0;
1137 }
1138 
1139 static size_t gtp_get_size(const struct net_device *dev)
1140 {
1141     return nla_total_size(sizeof(__u32)) + /* IFLA_GTP_PDP_HASHSIZE */
1142         nla_total_size(sizeof(__u32)) + /* IFLA_GTP_ROLE */
1143         nla_total_size(sizeof(__u8)); /* IFLA_GTP_RESTART_COUNT */
1144 }
1145 
1146 static int gtp_fill_info(struct sk_buff *skb, const struct net_device *dev)
1147 {
1148     struct gtp_dev *gtp = netdev_priv(dev);
1149 
1150     if (nla_put_u32(skb, IFLA_GTP_PDP_HASHSIZE, gtp->hash_size))
1151         goto nla_put_failure;
1152     if (nla_put_u32(skb, IFLA_GTP_ROLE, gtp->role))
1153         goto nla_put_failure;
1154     if (nla_put_u8(skb, IFLA_GTP_RESTART_COUNT, gtp->restart_count))
1155         goto nla_put_failure;
1156 
1157     return 0;
1158 
1159 nla_put_failure:
1160     return -EMSGSIZE;
1161 }
1162 
1163 static struct rtnl_link_ops gtp_link_ops __read_mostly = {
1164     .kind       = "gtp",
1165     .maxtype    = IFLA_GTP_MAX,
1166     .policy     = gtp_policy,
1167     .priv_size  = sizeof(struct gtp_dev),
1168     .setup      = gtp_link_setup,
1169     .validate   = gtp_validate,
1170     .newlink    = gtp_newlink,
1171     .dellink    = gtp_dellink,
1172     .get_size   = gtp_get_size,
1173     .fill_info  = gtp_fill_info,
1174 };
1175 
1176 static int gtp_hashtable_new(struct gtp_dev *gtp, int hsize)
1177 {
1178     int i;
1179 
1180     gtp->addr_hash = kmalloc_array(hsize, sizeof(struct hlist_head),
1181                        GFP_KERNEL | __GFP_NOWARN);
1182     if (gtp->addr_hash == NULL)
1183         return -ENOMEM;
1184 
1185     gtp->tid_hash = kmalloc_array(hsize, sizeof(struct hlist_head),
1186                       GFP_KERNEL | __GFP_NOWARN);
1187     if (gtp->tid_hash == NULL)
1188         goto err1;
1189 
1190     gtp->hash_size = hsize;
1191 
1192     for (i = 0; i < hsize; i++) {
1193         INIT_HLIST_HEAD(&gtp->addr_hash[i]);
1194         INIT_HLIST_HEAD(&gtp->tid_hash[i]);
1195     }
1196     return 0;
1197 err1:
1198     kfree(gtp->addr_hash);
1199     return -ENOMEM;
1200 }
1201 
1202 static struct sock *gtp_encap_enable_socket(int fd, int type,
1203                         struct gtp_dev *gtp)
1204 {
1205     struct udp_tunnel_sock_cfg tuncfg = {NULL};
1206     struct socket *sock;
1207     struct sock *sk;
1208     int err;
1209 
1210     pr_debug("enable gtp on %d, %d\n", fd, type);
1211 
1212     sock = sockfd_lookup(fd, &err);
1213     if (!sock) {
1214         pr_debug("gtp socket fd=%d not found\n", fd);
1215         return NULL;
1216     }
1217 
1218     sk = sock->sk;
1219     if (sk->sk_protocol != IPPROTO_UDP ||
1220         sk->sk_type != SOCK_DGRAM ||
1221         (sk->sk_family != AF_INET && sk->sk_family != AF_INET6)) {
1222         pr_debug("socket fd=%d not UDP\n", fd);
1223         sk = ERR_PTR(-EINVAL);
1224         goto out_sock;
1225     }
1226 
1227     lock_sock(sk);
1228     if (sk->sk_user_data) {
1229         sk = ERR_PTR(-EBUSY);
1230         goto out_rel_sock;
1231     }
1232 
1233     sock_hold(sk);
1234 
1235     tuncfg.sk_user_data = gtp;
1236     tuncfg.encap_type = type;
1237     tuncfg.encap_rcv = gtp_encap_recv;
1238     tuncfg.encap_destroy = gtp_encap_destroy;
1239 
1240     setup_udp_tunnel_sock(sock_net(sock->sk), sock, &tuncfg);
1241 
1242 out_rel_sock:
1243     release_sock(sock->sk);
1244 out_sock:
1245     sockfd_put(sock);
1246     return sk;
1247 }
1248 
1249 static int gtp_encap_enable(struct gtp_dev *gtp, struct nlattr *data[])
1250 {
1251     struct sock *sk1u = NULL;
1252     struct sock *sk0 = NULL;
1253 
1254     if (!data[IFLA_GTP_FD0] && !data[IFLA_GTP_FD1])
1255         return -EINVAL;
1256 
1257     if (data[IFLA_GTP_FD0]) {
1258         u32 fd0 = nla_get_u32(data[IFLA_GTP_FD0]);
1259 
1260         sk0 = gtp_encap_enable_socket(fd0, UDP_ENCAP_GTP0, gtp);
1261         if (IS_ERR(sk0))
1262             return PTR_ERR(sk0);
1263     }
1264 
1265     if (data[IFLA_GTP_FD1]) {
1266         u32 fd1 = nla_get_u32(data[IFLA_GTP_FD1]);
1267 
1268         sk1u = gtp_encap_enable_socket(fd1, UDP_ENCAP_GTP1U, gtp);
1269         if (IS_ERR(sk1u)) {
1270             gtp_encap_disable_sock(sk0);
1271             return PTR_ERR(sk1u);
1272         }
1273     }
1274 
1275     gtp->sk0 = sk0;
1276     gtp->sk1u = sk1u;
1277 
1278     return 0;
1279 }
1280 
1281 static struct gtp_dev *gtp_find_dev(struct net *src_net, struct nlattr *nla[])
1282 {
1283     struct gtp_dev *gtp = NULL;
1284     struct net_device *dev;
1285     struct net *net;
1286 
1287     /* Examine the link attributes and figure out which network namespace
1288      * we are talking about.
1289      */
1290     if (nla[GTPA_NET_NS_FD])
1291         net = get_net_ns_by_fd(nla_get_u32(nla[GTPA_NET_NS_FD]));
1292     else
1293         net = get_net(src_net);
1294 
1295     if (IS_ERR(net))
1296         return NULL;
1297 
1298     /* Check if there's an existing gtpX device to configure */
1299     dev = dev_get_by_index_rcu(net, nla_get_u32(nla[GTPA_LINK]));
1300     if (dev && dev->netdev_ops == &gtp_netdev_ops)
1301         gtp = netdev_priv(dev);
1302 
1303     put_net(net);
1304     return gtp;
1305 }
1306 
1307 static void ipv4_pdp_fill(struct pdp_ctx *pctx, struct genl_info *info)
1308 {
1309     pctx->gtp_version = nla_get_u32(info->attrs[GTPA_VERSION]);
1310     pctx->af = AF_INET;
1311     pctx->peer_addr_ip4.s_addr =
1312         nla_get_be32(info->attrs[GTPA_PEER_ADDRESS]);
1313     pctx->ms_addr_ip4.s_addr =
1314         nla_get_be32(info->attrs[GTPA_MS_ADDRESS]);
1315 
1316     switch (pctx->gtp_version) {
1317     case GTP_V0:
1318         /* According to TS 09.60, sections 7.5.1 and 7.5.2, the flow
1319          * label needs to be the same for uplink and downlink packets,
1320          * so let's annotate this.
1321          */
1322         pctx->u.v0.tid = nla_get_u64(info->attrs[GTPA_TID]);
1323         pctx->u.v0.flow = nla_get_u16(info->attrs[GTPA_FLOW]);
1324         break;
1325     case GTP_V1:
1326         pctx->u.v1.i_tei = nla_get_u32(info->attrs[GTPA_I_TEI]);
1327         pctx->u.v1.o_tei = nla_get_u32(info->attrs[GTPA_O_TEI]);
1328         break;
1329     default:
1330         break;
1331     }
1332 }
1333 
1334 static struct pdp_ctx *gtp_pdp_add(struct gtp_dev *gtp, struct sock *sk,
1335                    struct genl_info *info)
1336 {
1337     struct pdp_ctx *pctx, *pctx_tid = NULL;
1338     struct net_device *dev = gtp->dev;
1339     u32 hash_ms, hash_tid = 0;
1340     unsigned int version;
1341     bool found = false;
1342     __be32 ms_addr;
1343 
1344     ms_addr = nla_get_be32(info->attrs[GTPA_MS_ADDRESS]);
1345     hash_ms = ipv4_hashfn(ms_addr) % gtp->hash_size;
1346     version = nla_get_u32(info->attrs[GTPA_VERSION]);
1347 
1348     pctx = ipv4_pdp_find(gtp, ms_addr);
1349     if (pctx)
1350         found = true;
1351     if (version == GTP_V0)
1352         pctx_tid = gtp0_pdp_find(gtp,
1353                      nla_get_u64(info->attrs[GTPA_TID]));
1354     else if (version == GTP_V1)
1355         pctx_tid = gtp1_pdp_find(gtp,
1356                      nla_get_u32(info->attrs[GTPA_I_TEI]));
1357     if (pctx_tid)
1358         found = true;
1359 
1360     if (found) {
1361         if (info->nlhdr->nlmsg_flags & NLM_F_EXCL)
1362             return ERR_PTR(-EEXIST);
1363         if (info->nlhdr->nlmsg_flags & NLM_F_REPLACE)
1364             return ERR_PTR(-EOPNOTSUPP);
1365 
1366         if (pctx && pctx_tid)
1367             return ERR_PTR(-EEXIST);
1368         if (!pctx)
1369             pctx = pctx_tid;
1370 
1371         ipv4_pdp_fill(pctx, info);
1372 
1373         if (pctx->gtp_version == GTP_V0)
1374             netdev_dbg(dev, "GTPv0-U: update tunnel id = %llx (pdp %p)\n",
1375                    pctx->u.v0.tid, pctx);
1376         else if (pctx->gtp_version == GTP_V1)
1377             netdev_dbg(dev, "GTPv1-U: update tunnel id = %x/%x (pdp %p)\n",
1378                    pctx->u.v1.i_tei, pctx->u.v1.o_tei, pctx);
1379 
1380         return pctx;
1381 
1382     }
1383 
1384     pctx = kmalloc(sizeof(*pctx), GFP_ATOMIC);
1385     if (pctx == NULL)
1386         return ERR_PTR(-ENOMEM);
1387 
1388     sock_hold(sk);
1389     pctx->sk = sk;
1390     pctx->dev = gtp->dev;
1391     ipv4_pdp_fill(pctx, info);
1392     atomic_set(&pctx->tx_seq, 0);
1393 
1394     switch (pctx->gtp_version) {
1395     case GTP_V0:
1396         /* TS 09.60: "The flow label identifies unambiguously a GTP
1397          * flow.". We use the tid for this instead, I cannot find a
1398          * situation in which this doesn't unambiguosly identify the
1399          * PDP context.
1400          */
1401         hash_tid = gtp0_hashfn(pctx->u.v0.tid) % gtp->hash_size;
1402         break;
1403     case GTP_V1:
1404         hash_tid = gtp1u_hashfn(pctx->u.v1.i_tei) % gtp->hash_size;
1405         break;
1406     }
1407 
1408     hlist_add_head_rcu(&pctx->hlist_addr, &gtp->addr_hash[hash_ms]);
1409     hlist_add_head_rcu(&pctx->hlist_tid, &gtp->tid_hash[hash_tid]);
1410 
1411     switch (pctx->gtp_version) {
1412     case GTP_V0:
1413         netdev_dbg(dev, "GTPv0-U: new PDP ctx id=%llx ssgn=%pI4 ms=%pI4 (pdp=%p)\n",
1414                pctx->u.v0.tid, &pctx->peer_addr_ip4,
1415                &pctx->ms_addr_ip4, pctx);
1416         break;
1417     case GTP_V1:
1418         netdev_dbg(dev, "GTPv1-U: new PDP ctx id=%x/%x ssgn=%pI4 ms=%pI4 (pdp=%p)\n",
1419                pctx->u.v1.i_tei, pctx->u.v1.o_tei,
1420                &pctx->peer_addr_ip4, &pctx->ms_addr_ip4, pctx);
1421         break;
1422     }
1423 
1424     return pctx;
1425 }
1426 
1427 static void pdp_context_free(struct rcu_head *head)
1428 {
1429     struct pdp_ctx *pctx = container_of(head, struct pdp_ctx, rcu_head);
1430 
1431     sock_put(pctx->sk);
1432     kfree(pctx);
1433 }
1434 
1435 static void pdp_context_delete(struct pdp_ctx *pctx)
1436 {
1437     hlist_del_rcu(&pctx->hlist_tid);
1438     hlist_del_rcu(&pctx->hlist_addr);
1439     call_rcu(&pctx->rcu_head, pdp_context_free);
1440 }
1441 
1442 static int gtp_tunnel_notify(struct pdp_ctx *pctx, u8 cmd, gfp_t allocation);
1443 
1444 static int gtp_genl_new_pdp(struct sk_buff *skb, struct genl_info *info)
1445 {
1446     unsigned int version;
1447     struct pdp_ctx *pctx;
1448     struct gtp_dev *gtp;
1449     struct sock *sk;
1450     int err;
1451 
1452     if (!info->attrs[GTPA_VERSION] ||
1453         !info->attrs[GTPA_LINK] ||
1454         !info->attrs[GTPA_PEER_ADDRESS] ||
1455         !info->attrs[GTPA_MS_ADDRESS])
1456         return -EINVAL;
1457 
1458     version = nla_get_u32(info->attrs[GTPA_VERSION]);
1459 
1460     switch (version) {
1461     case GTP_V0:
1462         if (!info->attrs[GTPA_TID] ||
1463             !info->attrs[GTPA_FLOW])
1464             return -EINVAL;
1465         break;
1466     case GTP_V1:
1467         if (!info->attrs[GTPA_I_TEI] ||
1468             !info->attrs[GTPA_O_TEI])
1469             return -EINVAL;
1470         break;
1471 
1472     default:
1473         return -EINVAL;
1474     }
1475 
1476     rtnl_lock();
1477 
1478     gtp = gtp_find_dev(sock_net(skb->sk), info->attrs);
1479     if (!gtp) {
1480         err = -ENODEV;
1481         goto out_unlock;
1482     }
1483 
1484     if (version == GTP_V0)
1485         sk = gtp->sk0;
1486     else if (version == GTP_V1)
1487         sk = gtp->sk1u;
1488     else
1489         sk = NULL;
1490 
1491     if (!sk) {
1492         err = -ENODEV;
1493         goto out_unlock;
1494     }
1495 
1496     pctx = gtp_pdp_add(gtp, sk, info);
1497     if (IS_ERR(pctx)) {
1498         err = PTR_ERR(pctx);
1499     } else {
1500         gtp_tunnel_notify(pctx, GTP_CMD_NEWPDP, GFP_KERNEL);
1501         err = 0;
1502     }
1503 
1504 out_unlock:
1505     rtnl_unlock();
1506     return err;
1507 }
1508 
1509 static struct pdp_ctx *gtp_find_pdp_by_link(struct net *net,
1510                         struct nlattr *nla[])
1511 {
1512     struct gtp_dev *gtp;
1513 
1514     gtp = gtp_find_dev(net, nla);
1515     if (!gtp)
1516         return ERR_PTR(-ENODEV);
1517 
1518     if (nla[GTPA_MS_ADDRESS]) {
1519         __be32 ip = nla_get_be32(nla[GTPA_MS_ADDRESS]);
1520 
1521         return ipv4_pdp_find(gtp, ip);
1522     } else if (nla[GTPA_VERSION]) {
1523         u32 gtp_version = nla_get_u32(nla[GTPA_VERSION]);
1524 
1525         if (gtp_version == GTP_V0 && nla[GTPA_TID])
1526             return gtp0_pdp_find(gtp, nla_get_u64(nla[GTPA_TID]));
1527         else if (gtp_version == GTP_V1 && nla[GTPA_I_TEI])
1528             return gtp1_pdp_find(gtp, nla_get_u32(nla[GTPA_I_TEI]));
1529     }
1530 
1531     return ERR_PTR(-EINVAL);
1532 }
1533 
1534 static struct pdp_ctx *gtp_find_pdp(struct net *net, struct nlattr *nla[])
1535 {
1536     struct pdp_ctx *pctx;
1537 
1538     if (nla[GTPA_LINK])
1539         pctx = gtp_find_pdp_by_link(net, nla);
1540     else
1541         pctx = ERR_PTR(-EINVAL);
1542 
1543     if (!pctx)
1544         pctx = ERR_PTR(-ENOENT);
1545 
1546     return pctx;
1547 }
1548 
1549 static int gtp_genl_del_pdp(struct sk_buff *skb, struct genl_info *info)
1550 {
1551     struct pdp_ctx *pctx;
1552     int err = 0;
1553 
1554     if (!info->attrs[GTPA_VERSION])
1555         return -EINVAL;
1556 
1557     rcu_read_lock();
1558 
1559     pctx = gtp_find_pdp(sock_net(skb->sk), info->attrs);
1560     if (IS_ERR(pctx)) {
1561         err = PTR_ERR(pctx);
1562         goto out_unlock;
1563     }
1564 
1565     if (pctx->gtp_version == GTP_V0)
1566         netdev_dbg(pctx->dev, "GTPv0-U: deleting tunnel id = %llx (pdp %p)\n",
1567                pctx->u.v0.tid, pctx);
1568     else if (pctx->gtp_version == GTP_V1)
1569         netdev_dbg(pctx->dev, "GTPv1-U: deleting tunnel id = %x/%x (pdp %p)\n",
1570                pctx->u.v1.i_tei, pctx->u.v1.o_tei, pctx);
1571 
1572     gtp_tunnel_notify(pctx, GTP_CMD_DELPDP, GFP_ATOMIC);
1573     pdp_context_delete(pctx);
1574 
1575 out_unlock:
1576     rcu_read_unlock();
1577     return err;
1578 }
1579 
1580 static int gtp_genl_fill_info(struct sk_buff *skb, u32 snd_portid, u32 snd_seq,
1581                   int flags, u32 type, struct pdp_ctx *pctx)
1582 {
1583     void *genlh;
1584 
1585     genlh = genlmsg_put(skb, snd_portid, snd_seq, &gtp_genl_family, flags,
1586                 type);
1587     if (genlh == NULL)
1588         goto nlmsg_failure;
1589 
1590     if (nla_put_u32(skb, GTPA_VERSION, pctx->gtp_version) ||
1591         nla_put_u32(skb, GTPA_LINK, pctx->dev->ifindex) ||
1592         nla_put_be32(skb, GTPA_PEER_ADDRESS, pctx->peer_addr_ip4.s_addr) ||
1593         nla_put_be32(skb, GTPA_MS_ADDRESS, pctx->ms_addr_ip4.s_addr))
1594         goto nla_put_failure;
1595 
1596     switch (pctx->gtp_version) {
1597     case GTP_V0:
1598         if (nla_put_u64_64bit(skb, GTPA_TID, pctx->u.v0.tid, GTPA_PAD) ||
1599             nla_put_u16(skb, GTPA_FLOW, pctx->u.v0.flow))
1600             goto nla_put_failure;
1601         break;
1602     case GTP_V1:
1603         if (nla_put_u32(skb, GTPA_I_TEI, pctx->u.v1.i_tei) ||
1604             nla_put_u32(skb, GTPA_O_TEI, pctx->u.v1.o_tei))
1605             goto nla_put_failure;
1606         break;
1607     }
1608     genlmsg_end(skb, genlh);
1609     return 0;
1610 
1611 nlmsg_failure:
1612 nla_put_failure:
1613     genlmsg_cancel(skb, genlh);
1614     return -EMSGSIZE;
1615 }
1616 
1617 static int gtp_tunnel_notify(struct pdp_ctx *pctx, u8 cmd, gfp_t allocation)
1618 {
1619     struct sk_buff *msg;
1620     int ret;
1621 
1622     msg = nlmsg_new(NLMSG_DEFAULT_SIZE, allocation);
1623     if (!msg)
1624         return -ENOMEM;
1625 
1626     ret = gtp_genl_fill_info(msg, 0, 0, 0, cmd, pctx);
1627     if (ret < 0) {
1628         nlmsg_free(msg);
1629         return ret;
1630     }
1631 
1632     ret = genlmsg_multicast_netns(&gtp_genl_family, dev_net(pctx->dev), msg,
1633                       0, GTP_GENL_MCGRP, GFP_ATOMIC);
1634     return ret;
1635 }
1636 
1637 static int gtp_genl_get_pdp(struct sk_buff *skb, struct genl_info *info)
1638 {
1639     struct pdp_ctx *pctx = NULL;
1640     struct sk_buff *skb2;
1641     int err;
1642 
1643     if (!info->attrs[GTPA_VERSION])
1644         return -EINVAL;
1645 
1646     rcu_read_lock();
1647 
1648     pctx = gtp_find_pdp(sock_net(skb->sk), info->attrs);
1649     if (IS_ERR(pctx)) {
1650         err = PTR_ERR(pctx);
1651         goto err_unlock;
1652     }
1653 
1654     skb2 = genlmsg_new(NLMSG_GOODSIZE, GFP_ATOMIC);
1655     if (skb2 == NULL) {
1656         err = -ENOMEM;
1657         goto err_unlock;
1658     }
1659 
1660     err = gtp_genl_fill_info(skb2, NETLINK_CB(skb).portid, info->snd_seq,
1661                  0, info->nlhdr->nlmsg_type, pctx);
1662     if (err < 0)
1663         goto err_unlock_free;
1664 
1665     rcu_read_unlock();
1666     return genlmsg_unicast(genl_info_net(info), skb2, info->snd_portid);
1667 
1668 err_unlock_free:
1669     kfree_skb(skb2);
1670 err_unlock:
1671     rcu_read_unlock();
1672     return err;
1673 }
1674 
1675 static int gtp_genl_dump_pdp(struct sk_buff *skb,
1676                 struct netlink_callback *cb)
1677 {
1678     struct gtp_dev *last_gtp = (struct gtp_dev *)cb->args[2], *gtp;
1679     int i, j, bucket = cb->args[0], skip = cb->args[1];
1680     struct net *net = sock_net(skb->sk);
1681     struct pdp_ctx *pctx;
1682     struct gtp_net *gn;
1683 
1684     gn = net_generic(net, gtp_net_id);
1685 
1686     if (cb->args[4])
1687         return 0;
1688 
1689     rcu_read_lock();
1690     list_for_each_entry_rcu(gtp, &gn->gtp_dev_list, list) {
1691         if (last_gtp && last_gtp != gtp)
1692             continue;
1693         else
1694             last_gtp = NULL;
1695 
1696         for (i = bucket; i < gtp->hash_size; i++) {
1697             j = 0;
1698             hlist_for_each_entry_rcu(pctx, &gtp->tid_hash[i],
1699                          hlist_tid) {
1700                 if (j >= skip &&
1701                     gtp_genl_fill_info(skb,
1702                         NETLINK_CB(cb->skb).portid,
1703                         cb->nlh->nlmsg_seq,
1704                         NLM_F_MULTI,
1705                         cb->nlh->nlmsg_type, pctx)) {
1706                     cb->args[0] = i;
1707                     cb->args[1] = j;
1708                     cb->args[2] = (unsigned long)gtp;
1709                     goto out;
1710                 }
1711                 j++;
1712             }
1713             skip = 0;
1714         }
1715         bucket = 0;
1716     }
1717     cb->args[4] = 1;
1718 out:
1719     rcu_read_unlock();
1720     return skb->len;
1721 }
1722 
1723 static int gtp_genl_send_echo_req(struct sk_buff *skb, struct genl_info *info)
1724 {
1725     struct sk_buff *skb_to_send;
1726     __be32 src_ip, dst_ip;
1727     unsigned int version;
1728     struct gtp_dev *gtp;
1729     struct flowi4 fl4;
1730     struct rtable *rt;
1731     struct sock *sk;
1732     __be16 port;
1733     int len;
1734 
1735     if (!info->attrs[GTPA_VERSION] ||
1736         !info->attrs[GTPA_LINK] ||
1737         !info->attrs[GTPA_PEER_ADDRESS] ||
1738         !info->attrs[GTPA_MS_ADDRESS])
1739         return -EINVAL;
1740 
1741     version = nla_get_u32(info->attrs[GTPA_VERSION]);
1742     dst_ip = nla_get_be32(info->attrs[GTPA_PEER_ADDRESS]);
1743     src_ip = nla_get_be32(info->attrs[GTPA_MS_ADDRESS]);
1744 
1745     gtp = gtp_find_dev(sock_net(skb->sk), info->attrs);
1746     if (!gtp)
1747         return -ENODEV;
1748 
1749     if (!gtp->sk_created)
1750         return -EOPNOTSUPP;
1751     if (!(gtp->dev->flags & IFF_UP))
1752         return -ENETDOWN;
1753 
1754     if (version == GTP_V0) {
1755         struct gtp0_header *gtp0_h;
1756 
1757         len = LL_RESERVED_SPACE(gtp->dev) + sizeof(struct gtp0_header) +
1758             sizeof(struct iphdr) + sizeof(struct udphdr);
1759 
1760         skb_to_send = netdev_alloc_skb_ip_align(gtp->dev, len);
1761         if (!skb_to_send)
1762             return -ENOMEM;
1763 
1764         sk = gtp->sk0;
1765         port = htons(GTP0_PORT);
1766 
1767         gtp0_h = skb_push(skb_to_send, sizeof(struct gtp0_header));
1768         memset(gtp0_h, 0, sizeof(struct gtp0_header));
1769         gtp0_build_echo_msg(gtp0_h, GTP_ECHO_REQ);
1770     } else if (version == GTP_V1) {
1771         struct gtp1_header_long *gtp1u_h;
1772 
1773         len = LL_RESERVED_SPACE(gtp->dev) +
1774             sizeof(struct gtp1_header_long) +
1775             sizeof(struct iphdr) + sizeof(struct udphdr);
1776 
1777         skb_to_send = netdev_alloc_skb_ip_align(gtp->dev, len);
1778         if (!skb_to_send)
1779             return -ENOMEM;
1780 
1781         sk = gtp->sk1u;
1782         port = htons(GTP1U_PORT);
1783 
1784         gtp1u_h = skb_push(skb_to_send,
1785                    sizeof(struct gtp1_header_long));
1786         memset(gtp1u_h, 0, sizeof(struct gtp1_header_long));
1787         gtp1u_build_echo_msg(gtp1u_h, GTP_ECHO_REQ);
1788     } else {
1789         return -ENODEV;
1790     }
1791 
1792     rt = ip4_route_output_gtp(&fl4, sk, dst_ip, src_ip);
1793     if (IS_ERR(rt)) {
1794         netdev_dbg(gtp->dev, "no route for echo request to %pI4\n",
1795                &dst_ip);
1796         kfree_skb(skb_to_send);
1797         return -ENODEV;
1798     }
1799 
1800     udp_tunnel_xmit_skb(rt, sk, skb_to_send,
1801                 fl4.saddr, fl4.daddr,
1802                 fl4.flowi4_tos,
1803                 ip4_dst_hoplimit(&rt->dst),
1804                 0,
1805                 port, port,
1806                 !net_eq(sock_net(sk),
1807                     dev_net(gtp->dev)),
1808                 false);
1809     return 0;
1810 }
1811 
1812 static const struct nla_policy gtp_genl_policy[GTPA_MAX + 1] = {
1813     [GTPA_LINK]     = { .type = NLA_U32, },
1814     [GTPA_VERSION]      = { .type = NLA_U32, },
1815     [GTPA_TID]      = { .type = NLA_U64, },
1816     [GTPA_PEER_ADDRESS] = { .type = NLA_U32, },
1817     [GTPA_MS_ADDRESS]   = { .type = NLA_U32, },
1818     [GTPA_FLOW]     = { .type = NLA_U16, },
1819     [GTPA_NET_NS_FD]    = { .type = NLA_U32, },
1820     [GTPA_I_TEI]        = { .type = NLA_U32, },
1821     [GTPA_O_TEI]        = { .type = NLA_U32, },
1822 };
1823 
1824 static const struct genl_small_ops gtp_genl_ops[] = {
1825     {
1826         .cmd = GTP_CMD_NEWPDP,
1827         .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1828         .doit = gtp_genl_new_pdp,
1829         .flags = GENL_ADMIN_PERM,
1830     },
1831     {
1832         .cmd = GTP_CMD_DELPDP,
1833         .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1834         .doit = gtp_genl_del_pdp,
1835         .flags = GENL_ADMIN_PERM,
1836     },
1837     {
1838         .cmd = GTP_CMD_GETPDP,
1839         .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1840         .doit = gtp_genl_get_pdp,
1841         .dumpit = gtp_genl_dump_pdp,
1842         .flags = GENL_ADMIN_PERM,
1843     },
1844     {
1845         .cmd = GTP_CMD_ECHOREQ,
1846         .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
1847         .doit = gtp_genl_send_echo_req,
1848         .flags = GENL_ADMIN_PERM,
1849     },
1850 };
1851 
1852 static struct genl_family gtp_genl_family __ro_after_init = {
1853     .name       = "gtp",
1854     .version    = 0,
1855     .hdrsize    = 0,
1856     .maxattr    = GTPA_MAX,
1857     .policy = gtp_genl_policy,
1858     .netnsok    = true,
1859     .module     = THIS_MODULE,
1860     .small_ops  = gtp_genl_ops,
1861     .n_small_ops    = ARRAY_SIZE(gtp_genl_ops),
1862     .mcgrps     = gtp_genl_mcgrps,
1863     .n_mcgrps   = ARRAY_SIZE(gtp_genl_mcgrps),
1864 };
1865 
1866 static int __net_init gtp_net_init(struct net *net)
1867 {
1868     struct gtp_net *gn = net_generic(net, gtp_net_id);
1869 
1870     INIT_LIST_HEAD(&gn->gtp_dev_list);
1871     return 0;
1872 }
1873 
1874 static void __net_exit gtp_net_exit(struct net *net)
1875 {
1876     struct gtp_net *gn = net_generic(net, gtp_net_id);
1877     struct gtp_dev *gtp;
1878     LIST_HEAD(list);
1879 
1880     rtnl_lock();
1881     list_for_each_entry(gtp, &gn->gtp_dev_list, list)
1882         gtp_dellink(gtp->dev, &list);
1883 
1884     unregister_netdevice_many(&list);
1885     rtnl_unlock();
1886 }
1887 
1888 static struct pernet_operations gtp_net_ops = {
1889     .init   = gtp_net_init,
1890     .exit   = gtp_net_exit,
1891     .id = &gtp_net_id,
1892     .size   = sizeof(struct gtp_net),
1893 };
1894 
1895 static int __init gtp_init(void)
1896 {
1897     int err;
1898 
1899     get_random_bytes(&gtp_h_initval, sizeof(gtp_h_initval));
1900 
1901     err = rtnl_link_register(&gtp_link_ops);
1902     if (err < 0)
1903         goto error_out;
1904 
1905     err = genl_register_family(&gtp_genl_family);
1906     if (err < 0)
1907         goto unreg_rtnl_link;
1908 
1909     err = register_pernet_subsys(&gtp_net_ops);
1910     if (err < 0)
1911         goto unreg_genl_family;
1912 
1913     pr_info("GTP module loaded (pdp ctx size %zd bytes)\n",
1914         sizeof(struct pdp_ctx));
1915     return 0;
1916 
1917 unreg_genl_family:
1918     genl_unregister_family(&gtp_genl_family);
1919 unreg_rtnl_link:
1920     rtnl_link_unregister(&gtp_link_ops);
1921 error_out:
1922     pr_err("error loading GTP module loaded\n");
1923     return err;
1924 }
1925 late_initcall(gtp_init);
1926 
1927 static void __exit gtp_fini(void)
1928 {
1929     genl_unregister_family(&gtp_genl_family);
1930     rtnl_link_unregister(&gtp_link_ops);
1931     unregister_pernet_subsys(&gtp_net_ops);
1932 
1933     pr_info("GTP module unloaded\n");
1934 }
1935 module_exit(gtp_fini);
1936 
1937 MODULE_LICENSE("GPL");
1938 MODULE_AUTHOR("Harald Welte <hwelte@sysmocom.de>");
1939 MODULE_DESCRIPTION("Interface driver for GTP encapsulated traffic");
1940 MODULE_ALIAS_RTNL_LINK("gtp");
1941 MODULE_ALIAS_GENL_FAMILY("gtp");
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