net/mpls/mpls_gso.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  *  MPLS GSO Support
0004  *
0005  *  Authors: Simon Horman (horms@verge.net.au)
0006  *
0007  *  Based on: GSO portions of net/ipv4/gre.c
0008  */
0009
0010 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
0011
0012 #include <linux/err.h>
0013 #include <linux/module.h>
0014 #include <linux/netdev_features.h>
0015 #include <linux/netdevice.h>
0016 #include <linux/skbuff.h>
0017 #include <net/mpls.h>
0018
0019 static struct sk_buff *mpls_gso_segment(struct sk_buff *skb,
0020                        netdev_features_t features)
0021 {
0022     struct sk_buff *segs = ERR_PTR(-EINVAL);
0023     u16 mac_offset = skb->mac_header;
0024     netdev_features_t mpls_features;
0025     u16 mac_len = skb->mac_len;
0026     __be16 mpls_protocol;
0027     unsigned int mpls_hlen;
0028
0029     skb_reset_network_header(skb);
0030     mpls_hlen = skb_inner_network_header(skb) - skb_network_header(skb);
0031     if (unlikely(!mpls_hlen || mpls_hlen % MPLS_HLEN))
0032         goto out;
0033     if (unlikely(!pskb_may_pull(skb, mpls_hlen)))
0034         goto out;
0035
0036     /* Setup inner SKB. */
0037     mpls_protocol = skb->protocol;
0038     skb->protocol = skb->inner_protocol;
0039
0040     __skb_pull(skb, mpls_hlen);
0041
0042     skb->mac_len = 0;
0043     skb_reset_mac_header(skb);
0044
0045     /* Segment inner packet. */
0046     mpls_features = skb->dev->mpls_features & features;
0047     segs = skb_mac_gso_segment(skb, mpls_features);
0048     if (IS_ERR_OR_NULL(segs)) {
0049         skb_gso_error_unwind(skb, mpls_protocol, mpls_hlen, mac_offset,
0050                      mac_len);
0051         goto out;
0052     }
0053     skb = segs;
0054
0055     mpls_hlen += mac_len;
0056     do {
0057         skb->mac_len = mac_len;
0058         skb->protocol = mpls_protocol;
0059
0060         skb_reset_inner_network_header(skb);
0061
0062         __skb_push(skb, mpls_hlen);
0063
0064         skb_reset_mac_header(skb);
0065         skb_set_network_header(skb, mac_len);
0066     } while ((skb = skb->next));
0067
0068 out:
0069     return segs;
0070 }
0071
0072 static struct packet_offload mpls_mc_offload __read_mostly = {
0073     .type = cpu_to_be16(ETH_P_MPLS_MC),
0074     .priority = 15,
0075     .callbacks = {
0076         .gso_segment    =   mpls_gso_segment,
0077     },
0078 };
0079
0080 static struct packet_offload mpls_uc_offload __read_mostly = {
0081     .type = cpu_to_be16(ETH_P_MPLS_UC),
0082     .priority = 15,
0083     .callbacks = {
0084         .gso_segment    =   mpls_gso_segment,
0085     },
0086 };
0087
0088 static int __init mpls_gso_init(void)
0089 {
0090     pr_info("MPLS GSO support\n");
0091
0092     dev_add_offload(&mpls_uc_offload);
0093     dev_add_offload(&mpls_mc_offload);
0094
0095     return 0;
0096 }
0097
0098 static void __exit mpls_gso_exit(void)
0099 {
0100     dev_remove_offload(&mpls_uc_offload);
0101     dev_remove_offload(&mpls_mc_offload);
0102 }
0103
0104 module_init(mpls_gso_init);
0105 module_exit(mpls_gso_exit);
0106
0107 MODULE_DESCRIPTION("MPLS GSO support");
0108 MODULE_AUTHOR("Simon Horman (horms@verge.net.au)");
0109 MODULE_LICENSE("GPL");