bpf/progs/recvmsg4_prog.c

0001 // SPDX-License-Identifier: GPL-2.0
0002
0003 #include <linux/stddef.h>
0004 #include <linux/bpf.h>
0005 #include <linux/in.h>
0006 #include <sys/socket.h>
0007
0008 #include <bpf/bpf_helpers.h>
0009 #include <bpf/bpf_endian.h>
0010
0011 #include <bpf_sockopt_helpers.h>
0012
0013 #define SERV4_IP        0xc0a801feU /* 192.168.1.254 */
0014 #define SERV4_PORT      4040
0015
0016 SEC("cgroup/recvmsg4")
0017 int recvmsg4_prog(struct bpf_sock_addr *ctx)
0018 {
0019     struct bpf_sock *sk;
0020     __u32 user_ip4;
0021     __u16 user_port;
0022
0023     sk = ctx->sk;
0024     if (!sk)
0025         return 1;
0026
0027     if (sk->family != AF_INET)
0028         return 1;
0029
0030     if (ctx->type != SOCK_STREAM && ctx->type != SOCK_DGRAM)
0031         return 1;
0032
0033     if (!get_set_sk_priority(ctx))
0034         return 1;
0035
0036     ctx->user_ip4 = bpf_htonl(SERV4_IP);
0037     ctx->user_port = bpf_htons(SERV4_PORT);
0038
0039     return 1;
0040 }
0041
0042 char _license[] SEC("license") = "GPL";