bpf: Enable bpf_{g,s}etsockopt in BPF_CGROUP_UDP{4,6}_SENDMSG
Can be used to query/modify socket state for unconnected UDP sendmsg. Those hooks run as BPF_CGROUP_RUN_SA_PROG_LOCK and operate on a locked socket. Signed-off-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20210127232853.3753823-2-sdf@google.com
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@ -7023,6 +7023,8 @@ sock_addr_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
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case BPF_CGROUP_INET6_BIND:
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case BPF_CGROUP_INET4_CONNECT:
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case BPF_CGROUP_INET6_CONNECT:
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case BPF_CGROUP_UDP4_SENDMSG:
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case BPF_CGROUP_UDP6_SENDMSG:
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return &bpf_sock_addr_setsockopt_proto;
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default:
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return NULL;
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@ -7033,6 +7035,8 @@ sock_addr_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
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case BPF_CGROUP_INET6_BIND:
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case BPF_CGROUP_INET4_CONNECT:
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case BPF_CGROUP_INET6_CONNECT:
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case BPF_CGROUP_UDP4_SENDMSG:
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case BPF_CGROUP_UDP6_SENDMSG:
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return &bpf_sock_addr_getsockopt_proto;
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default:
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return NULL;
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@ -0,0 +1,21 @@
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/* SPDX-License-Identifier: GPL-2.0 */
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#include <sys/socket.h>
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#include <bpf/bpf_helpers.h>
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int get_set_sk_priority(void *ctx)
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{
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int prio;
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/* Verify that context allows calling bpf_getsockopt and
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* bpf_setsockopt by reading and writing back socket
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* priority.
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*/
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if (bpf_getsockopt(ctx, SOL_SOCKET, SO_PRIORITY, &prio, sizeof(prio)))
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return 0;
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if (bpf_setsockopt(ctx, SOL_SOCKET, SO_PRIORITY, &prio, sizeof(prio)))
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return 0;
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return 1;
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}
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@ -8,6 +8,8 @@
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_endian.h>
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#include <bpf_sockopt_helpers.h>
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#define SRC1_IP4 0xAC100001U /* 172.16.0.1 */
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#define SRC2_IP4 0x00000000U
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#define SRC_REWRITE_IP4 0x7f000004U
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@ -21,9 +23,14 @@ int _version SEC("version") = 1;
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SEC("cgroup/sendmsg4")
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int sendmsg_v4_prog(struct bpf_sock_addr *ctx)
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{
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int prio;
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if (ctx->type != SOCK_DGRAM)
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return 0;
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if (!get_set_sk_priority(ctx))
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return 0;
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/* Rewrite source. */
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if (ctx->msg_src_ip4 == bpf_htonl(SRC1_IP4) ||
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ctx->msg_src_ip4 == bpf_htonl(SRC2_IP4)) {
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@ -8,6 +8,8 @@
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_endian.h>
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#include <bpf_sockopt_helpers.h>
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#define SRC_REWRITE_IP6_0 0
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#define SRC_REWRITE_IP6_1 0
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#define SRC_REWRITE_IP6_2 0
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@ -28,6 +30,9 @@ int sendmsg_v6_prog(struct bpf_sock_addr *ctx)
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if (ctx->type != SOCK_DGRAM)
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return 0;
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if (!get_set_sk_priority(ctx))
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return 0;
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/* Rewrite source. */
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if (ctx->msg_src_ip6[3] == bpf_htonl(1) ||
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ctx->msg_src_ip6[3] == bpf_htonl(0)) {
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