From 6c49e65e0d462963b4fac97ebd87014342167027 Mon Sep 17 00:00:00 2001 From: Andrey Ignatov Date: Fri, 9 Nov 2018 10:54:01 -0800 Subject: [PATCH] bpf: Support socket lookup in CGROUP_SOCK_ADDR progs Make bpf_sk_lookup_tcp, bpf_sk_lookup_udp and bpf_sk_release helpers available in programs of type BPF_PROG_TYPE_CGROUP_SOCK_ADDR. Such programs operate on sockets and have access to socket and struct sockaddr passed by user to system calls such as sys_bind, sys_connect, sys_sendmsg. It's useful to be able to lookup other sockets from these programs. E.g. sys_connect may lookup IP:port endpoint and if there is a server socket bound to that endpoint ("server" can be defined by saddr & sport being zero), redirect client connection to it by rewriting IP:port in sockaddr passed to sys_connect. Signed-off-by: Andrey Ignatov Acked-by: Alexei Starovoitov Acked-by: Martin KaFai Lau Signed-off-by: Alexei Starovoitov --- net/core/filter.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) diff --git a/net/core/filter.c b/net/core/filter.c index f4ae933edf61..f6ca38a7d433 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -5042,6 +5042,43 @@ static const struct bpf_func_proto bpf_xdp_sk_lookup_tcp_proto = { .arg4_type = ARG_ANYTHING, .arg5_type = ARG_ANYTHING, }; + +BPF_CALL_5(bpf_sock_addr_sk_lookup_tcp, struct bpf_sock_addr_kern *, ctx, + struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags) +{ + return __bpf_sk_lookup(NULL, tuple, len, sock_net(ctx->sk), 0, + IPPROTO_TCP, netns_id, flags); +} + +static const struct bpf_func_proto bpf_sock_addr_sk_lookup_tcp_proto = { + .func = bpf_sock_addr_sk_lookup_tcp, + .gpl_only = false, + .ret_type = RET_PTR_TO_SOCKET_OR_NULL, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_PTR_TO_MEM, + .arg3_type = ARG_CONST_SIZE, + .arg4_type = ARG_ANYTHING, + .arg5_type = ARG_ANYTHING, +}; + +BPF_CALL_5(bpf_sock_addr_sk_lookup_udp, struct bpf_sock_addr_kern *, ctx, + struct bpf_sock_tuple *, tuple, u32, len, u64, netns_id, u64, flags) +{ + return __bpf_sk_lookup(NULL, tuple, len, sock_net(ctx->sk), 0, + IPPROTO_UDP, netns_id, flags); +} + +static const struct bpf_func_proto bpf_sock_addr_sk_lookup_udp_proto = { + .func = bpf_sock_addr_sk_lookup_udp, + .gpl_only = false, + .ret_type = RET_PTR_TO_SOCKET_OR_NULL, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_PTR_TO_MEM, + .arg3_type = ARG_CONST_SIZE, + .arg4_type = ARG_ANYTHING, + .arg5_type = ARG_ANYTHING, +}; + #endif /* CONFIG_INET */ bool bpf_helper_changes_pkt_data(void *func) @@ -5148,6 +5185,14 @@ sock_addr_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_get_socket_cookie_sock_addr_proto; case BPF_FUNC_get_local_storage: return &bpf_get_local_storage_proto; +#ifdef CONFIG_INET + case BPF_FUNC_sk_lookup_tcp: + return &bpf_sock_addr_sk_lookup_tcp_proto; + case BPF_FUNC_sk_lookup_udp: + return &bpf_sock_addr_sk_lookup_udp_proto; + case BPF_FUNC_sk_release: + return &bpf_sk_release_proto; +#endif /* CONFIG_INET */ default: return bpf_base_func_proto(func_id); } -- GitLab