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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> |
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6lowpan | ||
9p | ||
802 | ||
8021q | ||
appletalk | ||
atm | ||
ax25 | ||
batman-adv | ||
bluetooth | ||
bpf | ||
bridge | ||
caif | ||
can | ||
ceph | ||
core | ||
dcb | ||
dccp | ||
devlink | ||
dns_resolver | ||
dsa | ||
ethernet | ||
ethtool | ||
handshake | ||
hsr | ||
ieee802154 | ||
ife | ||
ipv4 | ||
ipv6 | ||
iucv | ||
kcm | ||
key | ||
l2tp | ||
l3mdev | ||
lapb | ||
llc | ||
mac80211 | ||
mac802154 | ||
mctp | ||
mpls | ||
mptcp | ||
ncsi | ||
netfilter | ||
netlabel | ||
netlink | ||
netrom | ||
nfc | ||
nsh | ||
openvswitch | ||
packet | ||
phonet | ||
psample | ||
qrtr | ||
rds | ||
rfkill | ||
rose | ||
rxrpc | ||
sched | ||
sctp | ||
smc | ||
strparser | ||
sunrpc | ||
switchdev | ||
tipc | ||
tls | ||
unix | ||
vmw_vsock | ||
wireless | ||
x25 | ||
xdp | ||
xfrm | ||
compat.c | ||
devres.c | ||
Kconfig | ||
Kconfig.debug | ||
Makefile | ||
socket.c | ||
sysctl_net.c |