Merge branch 'tcp-coalesce-merge-timestamps' (5bec11cf) · Commits · 戴 / test

Martin KaFai Lau says: ==================== tcp: Merge timestamp info when coalescing skbs This series is separated from the RFC series related to tcp_sendmsg(MSG_EOR) and it is targeting for the net branch. This patchset is focusing on fixing cases where TCP timestamp could be lost after coalescing skbs. A BPF prog is used to kprobe to sock_queue_err_skb() and print out the value of serr->ee.ee_data. The BPF prog (run-able from bcc) is attached here: BPF prog used for testing: ~~~~~ from __future__ import print_function from bcc import BPF bpf_text = """ int trace_err_skb(struct pt_regs *ctx) { struct sk_buff *skb = (struct sk_buff *)ctx->si; struct sock *sk = (struct sock *)ctx->di; struct sock_exterr_skb *serr; u32 ee_data = 0; if (!sk || !skb) return 0; serr = SKB_EXT_ERR(skb); bpf_probe_read(&ee_data, sizeof(ee_data), &serr->ee.ee_data); bpf_trace_printk("ee_data:%u\\n", ee_data); return 0; }; """ b = BPF(text=bpf_text) b.attach_kprobe(event="sock_queue_err_skb", fn_name="trace_err_skb") print("Attached to kprobe") b.trace_print() ==================== Signed-off-by:

David S. Miller <davem@davemloft.net>

include/net/tcp.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -552,6 +552,8 @@ void tcp_send_ack(struct sock *sk);
		void tcp_send_delayed_ack(struct sock *sk);
		void tcp_send_loss_probe(struct sock *sk);
		bool tcp_schedule_loss_probe(struct sock *sk);
		void tcp_skb_collapse_tstamp(struct sk_buff *skb,
		const struct sk_buff *next_skb);

		/* tcp_input.c */
		void tcp_resume_early_retransmit(struct sock *sk);

net/ipv4/tcp_input.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -1309,6 +1309,7 @@ static bool tcp_shifted_skb(struct sock sk, struct sk_buff skb,
		if (skb == tcp_highest_sack(sk))
		tcp_advance_highest_sack(sk, skb);

		tcp_skb_collapse_tstamp(prev, skb);
		tcp_unlink_write_queue(skb, sk);
		sk_wmem_free_skb(sk, skb);

net/ipv4/tcp_output.c

+16 −0

Original line number	Diff line number	Diff line
		@@ -2441,6 +2441,20 @@ u32 __tcp_select_window(struct sock *sk)
		return window;
		}

		void tcp_skb_collapse_tstamp(struct sk_buff *skb,
		const struct sk_buff *next_skb)
		{
		const struct skb_shared_info *next_shinfo = skb_shinfo(next_skb);
		u8 tsflags = next_shinfo->tx_flags & SKBTX_ANY_TSTAMP;

		if (unlikely(tsflags)) {
		struct skb_shared_info *shinfo = skb_shinfo(skb);

		shinfo->tx_flags \|= tsflags;
		shinfo->tskey = next_shinfo->tskey;
		}
		}

		/* Collapses two adjacent SKB's during retransmission. */
		static void tcp_collapse_retrans(struct sock sk, struct sk_buff skb)
		{
		@@ -2484,6 +2498,8 @@ static void tcp_collapse_retrans(struct sock sk, struct sk_buff skb)

		tcp_adjust_pcount(sk, next_skb, tcp_skb_pcount(next_skb));

		tcp_skb_collapse_tstamp(skb, next_skb);

		sk_wmem_free_skb(sk, next_skb);
		}

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