1 // SPDX-License-Identifier: GPL-2.0 2 // Copyright (c) 2018 Facebook 3 4 #include <string.h> 5 6 #include <linux/stddef.h> 7 #include <linux/bpf.h> 8 #include <linux/in.h> 9 #include <linux/in6.h> 10 #include <sys/socket.h> 11 12 #include "bpf_helpers.h" 13 #include "bpf_endian.h" 14 15 #define SRC_REWRITE_IP4 0x7f000004U 16 #define DST_REWRITE_IP4 0x7f000001U 17 #define DST_REWRITE_PORT4 4444 18 19 int _version SEC("version") = 1; 20 21 SEC("cgroup/connect4") connect_v4_prog(struct bpf_sock_addr * ctx)22int connect_v4_prog(struct bpf_sock_addr *ctx) 23 { 24 struct sockaddr_in sa; 25 26 /* Rewrite destination. */ 27 ctx->user_ip4 = bpf_htonl(DST_REWRITE_IP4); 28 ctx->user_port = bpf_htons(DST_REWRITE_PORT4); 29 30 if (ctx->type == SOCK_DGRAM || ctx->type == SOCK_STREAM) { 31 ///* Rewrite source. */ 32 memset(&sa, 0, sizeof(sa)); 33 34 sa.sin_family = AF_INET; 35 sa.sin_port = bpf_htons(0); 36 sa.sin_addr.s_addr = bpf_htonl(SRC_REWRITE_IP4); 37 38 if (bpf_bind(ctx, (struct sockaddr *)&sa, sizeof(sa)) != 0) 39 return 0; 40 } 41 42 return 1; 43 } 44 45 char _license[] SEC("license") = "GPL"; 46