305 lines
7.2 KiB
C
305 lines
7.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2019 Facebook */
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#include <linux/bpf.h>
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#include <netinet/in.h>
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#include <stdbool.h>
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_endian.h>
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#include "bpf_tcp_helpers.h"
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enum bpf_linum_array_idx {
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EGRESS_LINUM_IDX,
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INGRESS_LINUM_IDX,
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READ_SK_DST_PORT_LINUM_IDX,
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__NR_BPF_LINUM_ARRAY_IDX,
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};
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__uint(max_entries, __NR_BPF_LINUM_ARRAY_IDX);
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__type(key, __u32);
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__type(value, __u32);
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} linum_map SEC(".maps");
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struct bpf_spinlock_cnt {
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struct bpf_spin_lock lock;
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__u32 cnt;
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};
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struct {
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__uint(type, BPF_MAP_TYPE_SK_STORAGE);
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__uint(map_flags, BPF_F_NO_PREALLOC);
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__type(key, int);
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__type(value, struct bpf_spinlock_cnt);
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} sk_pkt_out_cnt SEC(".maps");
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struct {
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__uint(type, BPF_MAP_TYPE_SK_STORAGE);
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__uint(map_flags, BPF_F_NO_PREALLOC);
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__type(key, int);
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__type(value, struct bpf_spinlock_cnt);
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} sk_pkt_out_cnt10 SEC(".maps");
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struct bpf_tcp_sock listen_tp = {};
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struct sockaddr_in6 srv_sa6 = {};
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struct bpf_tcp_sock cli_tp = {};
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struct bpf_tcp_sock srv_tp = {};
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struct bpf_sock listen_sk = {};
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struct bpf_sock srv_sk = {};
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struct bpf_sock cli_sk = {};
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__u64 parent_cg_id = 0;
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__u64 child_cg_id = 0;
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__u64 lsndtime = 0;
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static bool is_loopback6(__u32 *a6)
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{
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return !a6[0] && !a6[1] && !a6[2] && a6[3] == bpf_htonl(1);
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}
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static void skcpy(struct bpf_sock *dst,
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const struct bpf_sock *src)
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{
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dst->bound_dev_if = src->bound_dev_if;
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dst->family = src->family;
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dst->type = src->type;
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dst->protocol = src->protocol;
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dst->mark = src->mark;
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dst->priority = src->priority;
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dst->src_ip4 = src->src_ip4;
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dst->src_ip6[0] = src->src_ip6[0];
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dst->src_ip6[1] = src->src_ip6[1];
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dst->src_ip6[2] = src->src_ip6[2];
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dst->src_ip6[3] = src->src_ip6[3];
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dst->src_port = src->src_port;
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dst->dst_ip4 = src->dst_ip4;
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dst->dst_ip6[0] = src->dst_ip6[0];
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dst->dst_ip6[1] = src->dst_ip6[1];
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dst->dst_ip6[2] = src->dst_ip6[2];
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dst->dst_ip6[3] = src->dst_ip6[3];
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dst->dst_port = src->dst_port;
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dst->state = src->state;
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}
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static void tpcpy(struct bpf_tcp_sock *dst,
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const struct bpf_tcp_sock *src)
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{
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dst->snd_cwnd = src->snd_cwnd;
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dst->srtt_us = src->srtt_us;
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dst->rtt_min = src->rtt_min;
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dst->snd_ssthresh = src->snd_ssthresh;
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dst->rcv_nxt = src->rcv_nxt;
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dst->snd_nxt = src->snd_nxt;
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dst->snd_una = src->snd_una;
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dst->mss_cache = src->mss_cache;
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dst->ecn_flags = src->ecn_flags;
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dst->rate_delivered = src->rate_delivered;
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dst->rate_interval_us = src->rate_interval_us;
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dst->packets_out = src->packets_out;
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dst->retrans_out = src->retrans_out;
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dst->total_retrans = src->total_retrans;
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dst->segs_in = src->segs_in;
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dst->data_segs_in = src->data_segs_in;
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dst->segs_out = src->segs_out;
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dst->data_segs_out = src->data_segs_out;
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dst->lost_out = src->lost_out;
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dst->sacked_out = src->sacked_out;
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dst->bytes_received = src->bytes_received;
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dst->bytes_acked = src->bytes_acked;
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}
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/* Always return CG_OK so that no pkt will be filtered out */
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#define CG_OK 1
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#define RET_LOG() ({ \
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linum = __LINE__; \
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bpf_map_update_elem(&linum_map, &linum_idx, &linum, BPF_ANY); \
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return CG_OK; \
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})
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SEC("cgroup_skb/egress")
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int egress_read_sock_fields(struct __sk_buff *skb)
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{
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struct bpf_spinlock_cnt cli_cnt_init = { .lock = 0, .cnt = 0xeB9F };
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struct bpf_spinlock_cnt *pkt_out_cnt, *pkt_out_cnt10;
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struct bpf_tcp_sock *tp, *tp_ret;
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struct bpf_sock *sk, *sk_ret;
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__u32 linum, linum_idx;
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struct tcp_sock *ktp;
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linum_idx = EGRESS_LINUM_IDX;
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sk = skb->sk;
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if (!sk)
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RET_LOG();
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/* Not testing the egress traffic or the listening socket,
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* which are covered by the cgroup_skb/ingress test program.
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*/
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if (sk->family != AF_INET6 || !is_loopback6(sk->src_ip6) ||
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sk->state == BPF_TCP_LISTEN)
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return CG_OK;
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if (sk->src_port == bpf_ntohs(srv_sa6.sin6_port)) {
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/* Server socket */
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sk_ret = &srv_sk;
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tp_ret = &srv_tp;
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} else if (sk->dst_port == srv_sa6.sin6_port) {
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/* Client socket */
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sk_ret = &cli_sk;
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tp_ret = &cli_tp;
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} else {
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/* Not the testing egress traffic */
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return CG_OK;
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}
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/* It must be a fullsock for cgroup_skb/egress prog */
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sk = bpf_sk_fullsock(sk);
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if (!sk)
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RET_LOG();
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/* Not the testing egress traffic */
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if (sk->protocol != IPPROTO_TCP)
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return CG_OK;
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tp = bpf_tcp_sock(sk);
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if (!tp)
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RET_LOG();
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skcpy(sk_ret, sk);
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tpcpy(tp_ret, tp);
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if (sk_ret == &srv_sk) {
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ktp = bpf_skc_to_tcp_sock(sk);
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if (!ktp)
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RET_LOG();
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lsndtime = ktp->lsndtime;
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child_cg_id = bpf_sk_cgroup_id(ktp);
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if (!child_cg_id)
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RET_LOG();
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parent_cg_id = bpf_sk_ancestor_cgroup_id(ktp, 2);
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if (!parent_cg_id)
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RET_LOG();
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/* The userspace has created it for srv sk */
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pkt_out_cnt = bpf_sk_storage_get(&sk_pkt_out_cnt, ktp, 0, 0);
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pkt_out_cnt10 = bpf_sk_storage_get(&sk_pkt_out_cnt10, ktp,
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0, 0);
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} else {
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pkt_out_cnt = bpf_sk_storage_get(&sk_pkt_out_cnt, sk,
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&cli_cnt_init,
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BPF_SK_STORAGE_GET_F_CREATE);
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pkt_out_cnt10 = bpf_sk_storage_get(&sk_pkt_out_cnt10,
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sk, &cli_cnt_init,
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BPF_SK_STORAGE_GET_F_CREATE);
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}
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if (!pkt_out_cnt || !pkt_out_cnt10)
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RET_LOG();
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/* Even both cnt and cnt10 have lock defined in their BTF,
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* intentionally one cnt takes lock while one does not
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* as a test for the spinlock support in BPF_MAP_TYPE_SK_STORAGE.
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*/
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pkt_out_cnt->cnt += 1;
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bpf_spin_lock(&pkt_out_cnt10->lock);
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pkt_out_cnt10->cnt += 10;
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bpf_spin_unlock(&pkt_out_cnt10->lock);
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return CG_OK;
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}
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SEC("cgroup_skb/ingress")
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int ingress_read_sock_fields(struct __sk_buff *skb)
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{
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struct bpf_tcp_sock *tp;
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__u32 linum, linum_idx;
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struct bpf_sock *sk;
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linum_idx = INGRESS_LINUM_IDX;
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sk = skb->sk;
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if (!sk)
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RET_LOG();
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/* Not the testing ingress traffic to the server */
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if (sk->family != AF_INET6 || !is_loopback6(sk->src_ip6) ||
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sk->src_port != bpf_ntohs(srv_sa6.sin6_port))
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return CG_OK;
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/* Only interested in the listening socket */
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if (sk->state != BPF_TCP_LISTEN)
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return CG_OK;
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/* It must be a fullsock for cgroup_skb/ingress prog */
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sk = bpf_sk_fullsock(sk);
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if (!sk)
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RET_LOG();
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tp = bpf_tcp_sock(sk);
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if (!tp)
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RET_LOG();
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skcpy(&listen_sk, sk);
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tpcpy(&listen_tp, tp);
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return CG_OK;
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}
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/*
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* NOTE: 4-byte load from bpf_sock at dst_port offset is quirky. It
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* gets rewritten by the access converter to a 2-byte load for
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* backward compatibility. Treating the load result as a be16 value
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* makes the code portable across little- and big-endian platforms.
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*/
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static __noinline bool sk_dst_port__load_word(struct bpf_sock *sk)
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{
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__u32 *word = (__u32 *)&sk->dst_port;
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return word[0] == bpf_htons(0xcafe);
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}
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static __noinline bool sk_dst_port__load_half(struct bpf_sock *sk)
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{
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__u16 *half = (__u16 *)&sk->dst_port;
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return half[0] == bpf_htons(0xcafe);
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}
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static __noinline bool sk_dst_port__load_byte(struct bpf_sock *sk)
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{
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__u8 *byte = (__u8 *)&sk->dst_port;
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return byte[0] == 0xca && byte[1] == 0xfe;
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}
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SEC("cgroup_skb/egress")
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int read_sk_dst_port(struct __sk_buff *skb)
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{
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__u32 linum, linum_idx;
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struct bpf_sock *sk;
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linum_idx = READ_SK_DST_PORT_LINUM_IDX;
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sk = skb->sk;
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if (!sk)
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RET_LOG();
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/* Ignore everything but the SYN from the client socket */
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if (sk->state != BPF_TCP_SYN_SENT)
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return CG_OK;
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if (!sk_dst_port__load_word(sk))
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RET_LOG();
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if (!sk_dst_port__load_half(sk))
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RET_LOG();
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if (!sk_dst_port__load_byte(sk))
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RET_LOG();
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return CG_OK;
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}
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char _license[] SEC("license") = "GPL";
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