// SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2018 Facebook #include <string.h> #include <linux/stddef.h> #include <linux/bpf.h> #include <linux/in.h> #include <linux/in6.h> #include <sys/socket.h> #include <bpf/bpf_helpers.h> #include <bpf/bpf_endian.h> #define SRC_REWRITE_IP6_0 0 #define SRC_REWRITE_IP6_1 0 #define SRC_REWRITE_IP6_2 0 #define SRC_REWRITE_IP6_3 6 #define DST_REWRITE_IP6_0 0 #define DST_REWRITE_IP6_1 0 #define DST_REWRITE_IP6_2 0 #define DST_REWRITE_IP6_3 1 #define DST_REWRITE_PORT6 6666 SEC("cgroup/connect6") int connect_v6_prog(struct bpf_sock_addr *ctx) { struct bpf_sock_tuple tuple = {}; struct sockaddr_in6 sa; struct bpf_sock *sk; /* Verify that new destination is available. */ memset(&tuple.ipv6.saddr, 0, sizeof(tuple.ipv6.saddr)); memset(&tuple.ipv6.sport, 0, sizeof(tuple.ipv6.sport)); tuple.ipv6.daddr[0] = bpf_htonl(DST_REWRITE_IP6_0); tuple.ipv6.daddr[1] = bpf_htonl(DST_REWRITE_IP6_1); tuple.ipv6.daddr[2] = bpf_htonl(DST_REWRITE_IP6_2); tuple.ipv6.daddr[3] = bpf_htonl(DST_REWRITE_IP6_3); tuple.ipv6.dport = bpf_htons(DST_REWRITE_PORT6); if (ctx->type != SOCK_STREAM && ctx->type != SOCK_DGRAM) return 0; else if (ctx->type == SOCK_STREAM) sk = bpf_sk_lookup_tcp(ctx, &tuple, sizeof(tuple.ipv6), BPF_F_CURRENT_NETNS, 0); else sk = bpf_sk_lookup_udp(ctx, &tuple, sizeof(tuple.ipv6), BPF_F_CURRENT_NETNS, 0); if (!sk) return 0; if (sk->src_ip6[0] != tuple.ipv6.daddr[0] || sk->src_ip6[1] != tuple.ipv6.daddr[1] || sk->src_ip6[2] != tuple.ipv6.daddr[2] || sk->src_ip6[3] != tuple.ipv6.daddr[3] || sk->src_port != DST_REWRITE_PORT6) { bpf_sk_release(sk); return 0; } bpf_sk_release(sk); /* Rewrite destination. */ ctx->user_ip6[0] = bpf_htonl(DST_REWRITE_IP6_0); ctx->user_ip6[1] = bpf_htonl(DST_REWRITE_IP6_1); ctx->user_ip6[2] = bpf_htonl(DST_REWRITE_IP6_2); ctx->user_ip6[3] = bpf_htonl(DST_REWRITE_IP6_3); ctx->user_port = bpf_htons(DST_REWRITE_PORT6); /* Rewrite source. */ memset(&sa, 0, sizeof(sa)); sa.sin6_family = AF_INET6; sa.sin6_port = bpf_htons(0); sa.sin6_addr.s6_addr32[0] = bpf_htonl(SRC_REWRITE_IP6_0); sa.sin6_addr.s6_addr32[1] = bpf_htonl(SRC_REWRITE_IP6_1); sa.sin6_addr.s6_addr32[2] = bpf_htonl(SRC_REWRITE_IP6_2); sa.sin6_addr.s6_addr32[3] = bpf_htonl(SRC_REWRITE_IP6_3); if (bpf_bind(ctx, (struct sockaddr *)&sa, sizeof(sa)) != 0) return 0; return 1; } char _license[] SEC("license") = "GPL";