Commit 79636038 authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

ipv4: tcp: give socket pointer to control skbs 



ip_send_unicast_reply() send orphaned 'control packets'.

These are RST packets and also ACK packets sent from TIME_WAIT.

Some eBPF programs would prefer to have a meaningful skb->sk
pointer as much as possible.

This means that TCP can now attach TIME_WAIT sockets to outgoing
skbs.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: default avatarBrian Vazquez <brianvv@google.com>
Link: https://patch.msgid.link/20241010174817.1543642-6-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 507a9673

include/net/ip.h

+2 −1
Original line number Diff line number Diff line
@@ -288,7 +288,8 @@ static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg) 
	return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;

}



void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,

void ip_send_unicast_reply(struct sock *sk, const struct sock *orig_sk,

			   struct sk_buff *skb,

			   const struct ip_options *sopt,

			   __be32 daddr, __be32 saddr,

			   const struct ip_reply_arg *arg,

net/ipv4/ip_output.c

+4 −1
Original line number Diff line number Diff line
@@ -1596,7 +1596,8 @@ static int ip_reply_glue_bits(void *dptr, char *to, int offset, 
 *	Generic function to send a packet as reply to another packet.

 *	Used to send some TCP resets/acks so far.

 */

void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,

void ip_send_unicast_reply(struct sock *sk, const struct sock *orig_sk,

			   struct sk_buff *skb,

			   const struct ip_options *sopt,

			   __be32 daddr, __be32 saddr,

			   const struct ip_reply_arg *arg,
@@ -1662,6 +1663,8 @@ void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb, 
			  arg->csumoffset) = csum_fold(csum_add(nskb->csum,

								arg->csum));

		nskb->ip_summed = CHECKSUM_NONE;

		if (orig_sk)

			skb_set_owner_edemux(nskb, (struct sock *)orig_sk);

		if (transmit_time)

			nskb->tstamp_type = SKB_CLOCK_MONOTONIC;

		if (txhash)

net/ipv4/tcp_ipv4.c

+2 −2
Original line number Diff line number Diff line
@@ -907,7 +907,7 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb, 
		ctl_sk->sk_mark = 0;

		ctl_sk->sk_priority = 0;

	}

	ip_send_unicast_reply(ctl_sk,

	ip_send_unicast_reply(ctl_sk, sk,

			      skb, &TCP_SKB_CB(skb)->header.h4.opt,

			      ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,

			      &arg, arg.iov[0].iov_len,
@@ -1021,7 +1021,7 @@ static void tcp_v4_send_ack(const struct sock *sk, 
	ctl_sk->sk_priority = (sk->sk_state == TCP_TIME_WAIT) ?

			   inet_twsk(sk)->tw_priority : READ_ONCE(sk->sk_priority);

	transmit_time = tcp_transmit_time(sk);

	ip_send_unicast_reply(ctl_sk,

	ip_send_unicast_reply(ctl_sk, sk,

			      skb, &TCP_SKB_CB(skb)->header.h4.opt,

			      ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,

			      &arg, arg.iov[0].iov_len,