mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-28 13:22:57 +00:00
e472f88891
This patch adds a new kfunc available at TC hook to support arbitrary SYN Cookie. The basic usage is as follows: struct bpf_tcp_req_attrs attrs = { .mss = mss, .wscale_ok = wscale_ok, .rcv_wscale = rcv_wscale, /* Server's WScale < 15 */ .snd_wscale = snd_wscale, /* Client's WScale < 15 */ .tstamp_ok = tstamp_ok, .rcv_tsval = tsval, .rcv_tsecr = tsecr, /* Server's Initial TSval */ .usec_ts_ok = usec_ts_ok, .sack_ok = sack_ok, .ecn_ok = ecn_ok, } skc = bpf_skc_lookup_tcp(...); sk = (struct sock *)bpf_skc_to_tcp_sock(skc); bpf_sk_assign_tcp_reqsk(skb, sk, attrs, sizeof(attrs)); bpf_sk_release(skc); bpf_sk_assign_tcp_reqsk() takes skb, a listener sk, and struct bpf_tcp_req_attrs and allocates reqsk and configures it. Then, bpf_sk_assign_tcp_reqsk() links reqsk with skb and the listener. The notable thing here is that we do not hold refcnt for both reqsk and listener. To differentiate that, we mark reqsk->syncookie, which is only used in TX for now. So, if reqsk->syncookie is 1 in RX, it means that the reqsk is allocated by kfunc. When skb is freed, sock_pfree() checks if reqsk->syncookie is 1, and in that case, we set NULL to reqsk->rsk_listener before calling reqsk_free() as reqsk does not hold a refcnt of the listener. When the TCP stack looks up a socket from the skb, we steal the listener from the reqsk in skb_steal_sock() and create a full sk in cookie_v[46]_check(). The refcnt of reqsk will finally be set to 1 in tcp_get_cookie_sock() after creating a full sk. Note that we can extend struct bpf_tcp_req_attrs in the future when we add a new attribute that is determined in 3WHS. Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Link: https://lore.kernel.org/r/20240115205514.68364-6-kuniyu@amazon.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> |
||
---|---|---|
.. | ||
bpf_sk_storage.c | ||
datagram.c | ||
dev.c | ||
dev.h | ||
dev_addr_lists.c | ||
dev_addr_lists_test.c | ||
dev_ioctl.c | ||
drop_monitor.c | ||
dst.c | ||
dst_cache.c | ||
failover.c | ||
fib_notifier.c | ||
fib_rules.c | ||
filter.c | ||
flow_dissector.c | ||
flow_offload.c | ||
gen_estimator.c | ||
gen_stats.c | ||
gro.c | ||
gro_cells.c | ||
gso.c | ||
gso_test.c | ||
hwbm.c | ||
link_watch.c | ||
lwt_bpf.c | ||
lwtunnel.c | ||
Makefile | ||
neighbour.c | ||
net-procfs.c | ||
net-sysfs.c | ||
net-sysfs.h | ||
net-traces.c | ||
net_namespace.c | ||
netclassid_cgroup.c | ||
netdev-genl-gen.c | ||
netdev-genl-gen.h | ||
netdev-genl.c | ||
netevent.c | ||
netpoll.c | ||
netprio_cgroup.c | ||
of_net.c | ||
page_pool.c | ||
page_pool_priv.h | ||
page_pool_user.c | ||
pktgen.c | ||
ptp_classifier.c | ||
request_sock.c | ||
rtnetlink.c | ||
scm.c | ||
secure_seq.c | ||
selftests.c | ||
skbuff.c | ||
skmsg.c | ||
sock.c | ||
sock_destructor.h | ||
sock_diag.c | ||
sock_map.c | ||
sock_reuseport.c | ||
stream.c | ||
sysctl_net_core.c | ||
timestamping.c | ||
tso.c | ||
utils.c | ||
xdp.c |