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selftests/bpf: Implement sample tcp/tcp6 bpf_iter programs
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In my VM, I got identical result compared to /proc/net/{tcp,tcp6}.
For tcp6:
  $ cat /proc/net/tcp6
    sl  local_address                         remote_address                        st tx_queue rx_queue tr tm->when retrnsmt   uid  timeout inode
     0: 00000000000000000000000000000000:0016 00000000000000000000000000000000:0000 0A 00000000:00000000 00:00000001 00000000     0        0 17955 1 000000003eb3102e 100 0 0 10 0

  $ cat /sys/fs/bpf/p1
    sl  local_address                         remote_address                        st tx_queue rx_queue tr tm->when retrnsmt   uid  timeout inode
     0: 00000000000000000000000000000000:0016 00000000000000000000000000000000:0000 0A 00000000:00000000 00:00000000 00000000     0        0 17955 1 000000003eb3102e 100 0 0 10 0

For tcp:
  $ cat /proc/net/tcp
  sl  local_address rem_address   st tx_queue rx_queue tr tm->when retrnsmt   uid  timeout inode
   0: 00000000:0016 00000000:0000 0A 00000000:00000000 00:00000000 00000000     0        0 2666 1 000000007152e43f 100 0 0 10 0
  $ cat /sys/fs/bpf/p2
  sl  local_address                         remote_address                        st tx_queue rx_queue tr tm->when retrnsmt   uid  timeout inode
   1: 00000000:0016 00000000:0000 0A 00000000:00000000 00:00000000 00000000     0        0 2666 1 000000007152e43f 100 0 0 10 0

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200623230820.3989165-1-yhs@fb.com
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Yonghong Song authored and Alexei Starovoitov committed Jun 25, 2020
1 parent 3982bfa commit 2767c97
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15 changes: 15 additions & 0 deletions tools/testing/selftests/bpf/progs/bpf_iter.h
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Original file line number Diff line number Diff line change
Expand Up @@ -7,13 +7,17 @@
#define bpf_iter__netlink bpf_iter__netlink___not_used
#define bpf_iter__task bpf_iter__task___not_used
#define bpf_iter__task_file bpf_iter__task_file___not_used
#define bpf_iter__tcp bpf_iter__tcp___not_used
#define tcp6_sock tcp6_sock___not_used
#include "vmlinux.h"
#undef bpf_iter_meta
#undef bpf_iter__bpf_map
#undef bpf_iter__ipv6_route
#undef bpf_iter__netlink
#undef bpf_iter__task
#undef bpf_iter__task_file
#undef bpf_iter__tcp
#undef tcp6_sock

struct bpf_iter_meta {
struct seq_file *seq;
Expand Down Expand Up @@ -47,3 +51,14 @@ struct bpf_iter__bpf_map {
struct bpf_iter_meta *meta;
struct bpf_map *map;
} __attribute__((preserve_access_index));

struct bpf_iter__tcp {
struct bpf_iter_meta *meta;
struct sock_common *sk_common;
uid_t uid;
} __attribute__((preserve_access_index));

struct tcp6_sock {
struct tcp_sock tcp;
struct ipv6_pinfo inet6;
} __attribute__((preserve_access_index));
234 changes: 234 additions & 0 deletions tools/testing/selftests/bpf/progs/bpf_iter_tcp4.c
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Original file line number Diff line number Diff line change
@@ -0,0 +1,234 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020 Facebook */
#include "bpf_iter.h"
#include "bpf_tracing_net.h"
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
#include <bpf/bpf_endian.h>

char _license[] SEC("license") = "GPL";

static int hlist_unhashed_lockless(const struct hlist_node *h)
{
return !(h->pprev);
}

static int timer_pending(const struct timer_list * timer)
{
return !hlist_unhashed_lockless(&timer->entry);
}

extern unsigned CONFIG_HZ __kconfig;

#define USER_HZ 100
#define NSEC_PER_SEC 1000000000ULL
static clock_t jiffies_to_clock_t(unsigned long x)
{
/* The implementation here tailored to a particular
* setting of USER_HZ.
*/
u64 tick_nsec = (NSEC_PER_SEC + CONFIG_HZ/2) / CONFIG_HZ;
u64 user_hz_nsec = NSEC_PER_SEC / USER_HZ;

if ((tick_nsec % user_hz_nsec) == 0) {
if (CONFIG_HZ < USER_HZ)
return x * (USER_HZ / CONFIG_HZ);
else
return x / (CONFIG_HZ / USER_HZ);
}
return x * tick_nsec/user_hz_nsec;
}

static clock_t jiffies_delta_to_clock_t(long delta)
{
if (delta <= 0)
return 0;

return jiffies_to_clock_t(delta);
}

static long sock_i_ino(const struct sock *sk)
{
const struct socket *sk_socket = sk->sk_socket;
const struct inode *inode;
unsigned long ino;

if (!sk_socket)
return 0;

inode = &container_of(sk_socket, struct socket_alloc, socket)->vfs_inode;
bpf_probe_read(&ino, sizeof(ino), &inode->i_ino);
return ino;
}

static bool
inet_csk_in_pingpong_mode(const struct inet_connection_sock *icsk)
{
return icsk->icsk_ack.pingpong >= TCP_PINGPONG_THRESH;
}

static bool tcp_in_initial_slowstart(const struct tcp_sock *tcp)
{
return tcp->snd_ssthresh >= TCP_INFINITE_SSTHRESH;
}

static int dump_tcp_sock(struct seq_file *seq, struct tcp_sock *tp,
uid_t uid, __u32 seq_num)
{
const struct inet_connection_sock *icsk;
const struct fastopen_queue *fastopenq;
const struct inet_sock *inet;
unsigned long timer_expires;
const struct sock *sp;
__u16 destp, srcp;
__be32 dest, src;
int timer_active;
int rx_queue;
int state;

icsk = &tp->inet_conn;
inet = &icsk->icsk_inet;
sp = &inet->sk;
fastopenq = &icsk->icsk_accept_queue.fastopenq;

dest = inet->inet_daddr;
src = inet->inet_rcv_saddr;
destp = bpf_ntohs(inet->inet_dport);
srcp = bpf_ntohs(inet->inet_sport);

if (icsk->icsk_pending == ICSK_TIME_RETRANS ||
icsk->icsk_pending == ICSK_TIME_REO_TIMEOUT ||
icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) {
timer_active = 1;
timer_expires = icsk->icsk_timeout;
} else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
timer_active = 4;
timer_expires = icsk->icsk_timeout;
} else if (timer_pending(&sp->sk_timer)) {
timer_active = 2;
timer_expires = sp->sk_timer.expires;
} else {
timer_active = 0;
timer_expires = bpf_jiffies64();
}

state = sp->sk_state;
if (state == TCP_LISTEN) {
rx_queue = sp->sk_ack_backlog;
} else {
rx_queue = tp->rcv_nxt - tp->copied_seq;
if (rx_queue < 0)
rx_queue = 0;
}

BPF_SEQ_PRINTF(seq, "%4d: %08X:%04X %08X:%04X ",
seq_num, src, srcp, destp, destp);
BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d ",
state,
tp->write_seq - tp->snd_una, rx_queue,
timer_active,
jiffies_delta_to_clock_t(timer_expires - bpf_jiffies64()),
icsk->icsk_retransmits, uid,
icsk->icsk_probes_out,
sock_i_ino(sp),
sp->sk_refcnt.refs.counter);
BPF_SEQ_PRINTF(seq, "%pK %lu %lu %u %u %d\n",
tp,
jiffies_to_clock_t(icsk->icsk_rto),
jiffies_to_clock_t(icsk->icsk_ack.ato),
(icsk->icsk_ack.quick << 1) | inet_csk_in_pingpong_mode(icsk),
tp->snd_cwnd,
state == TCP_LISTEN ? fastopenq->max_qlen
: (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)
);

return 0;
}

static int dump_tw_sock(struct seq_file *seq, struct tcp_timewait_sock *ttw,
uid_t uid, __u32 seq_num)
{
struct inet_timewait_sock *tw = &ttw->tw_sk;
__u16 destp, srcp;
__be32 dest, src;
long delta;

delta = tw->tw_timer.expires - bpf_jiffies64();
dest = tw->tw_daddr;
src = tw->tw_rcv_saddr;
destp = bpf_ntohs(tw->tw_dport);
srcp = bpf_ntohs(tw->tw_sport);

BPF_SEQ_PRINTF(seq, "%4d: %08X:%04X %08X:%04X ",
seq_num, src, srcp, dest, destp);

BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
tw->tw_substate, 0, 0,
3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
tw->tw_refcnt.refs.counter, tw);

return 0;
}

static int dump_req_sock(struct seq_file *seq, struct tcp_request_sock *treq,
uid_t uid, __u32 seq_num)
{
struct inet_request_sock *irsk = &treq->req;
struct request_sock *req = &irsk->req;
long ttd;

ttd = req->rsk_timer.expires - bpf_jiffies64();

if (ttd < 0)
ttd = 0;

BPF_SEQ_PRINTF(seq, "%4d: %08X:%04X %08X:%04X ",
seq_num, irsk->ir_loc_addr,
irsk->ir_num, irsk->ir_rmt_addr,
bpf_ntohs(irsk->ir_rmt_port));
BPF_SEQ_PRINTF(seq, "%02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK\n",
TCP_SYN_RECV, 0, 0, 1, jiffies_to_clock_t(ttd),
req->num_timeout, uid, 0, 0, 0, req);

return 0;
}

SEC("iter/tcp")
int dump_tcp4(struct bpf_iter__tcp *ctx)
{
struct sock_common *sk_common = ctx->sk_common;
struct seq_file *seq = ctx->meta->seq;
struct tcp_timewait_sock *tw;
struct tcp_request_sock *req;
struct tcp_sock *tp;
uid_t uid = ctx->uid;
__u32 seq_num;

if (sk_common == (void *)0)
return 0;

seq_num = ctx->meta->seq_num;
if (seq_num == 0)
BPF_SEQ_PRINTF(seq, " sl "
"local_address "
"rem_address "
"st tx_queue rx_queue tr tm->when retrnsmt"
" uid timeout inode\n");

if (sk_common->skc_family != AF_INET)
return 0;

tp = bpf_skc_to_tcp_sock(sk_common);
if (tp)
return dump_tcp_sock(seq, tp, uid, seq_num);

tw = bpf_skc_to_tcp_timewait_sock(sk_common);
if (tw)
return dump_tw_sock(seq, tw, uid, seq_num);

req = bpf_skc_to_tcp_request_sock(sk_common);
if (req)
return dump_req_sock(seq, req, uid, seq_num);

return 0;
}
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