tcp: fix for splice receive when used with software LRO (db43a282) · Commits · 戴 / test

If an skb has nr_frags set to zero but its frag_list is not empty (as it can happen if software LRO is enabled), and a previous tcp_read_sock has consumed the linear part of the skb, then __skb_splice_bits: (a) incorrectly reports an error and (b) forgets to update the offset to account for the linear part Any of the two problems will cause the subsequent __skb_splice_bits call (the one that handles the frag_list skbs) to either skip data, or, if the unadjusted offset is greater then the size of the next skb in the frag_list, make tcp_splice_read loop forever. Signed-off-by:

Octavian Purdila <opurdila@ixiacom.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/core/skbuff.c

+12 −5

Original line number	Diff line number	Diff line
		@@ -1292,12 +1292,14 @@ static int __skb_splice_bits(struct sk_buff skb, unsigned int offset,
		{
		unsigned int nr_pages = spd->nr_pages;
		unsigned int poff, plen, len, toff, tlen;
		int headlen, seg;
		int headlen, seg, error = 0;

		toff = *offset;
		tlen = *total_len;
		if (!tlen)
		if (!tlen) {
		error = 1;
		goto err;
		}

		/*
		* if the offset is greater than the linear part, go directly to
		@@ -1339,7 +1341,8 @@ static int __skb_splice_bits(struct sk_buff skb, unsigned int offset,
		* just jump directly to update and return, no point
		* in going over fragments when the output is full.
		*/
		if (spd_fill_page(spd, virt_to_page(p), plen, poff, skb))
		error = spd_fill_page(spd, virt_to_page(p), plen, poff, skb);
		if (error)
		goto done;

		tlen -= plen;
		@@ -1369,7 +1372,8 @@ map_frag:
		if (!plen)
		break;

		if (spd_fill_page(spd, f->page, plen, poff, skb))
		error = spd_fill_page(spd, f->page, plen, poff, skb);
		if (error)
		break;

		tlen -= plen;
		@@ -1382,7 +1386,10 @@ done:
		return 0;
		}
		err:
		return 1;
		/* update the offset to reflect the linear part skip, if any */
		if (!error)
		*offset = toff;
		return error;
		}

		/*

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