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			108 lines
		
	
	
		
			3.3 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
			
		
		
	
	
			108 lines
		
	
	
		
			3.3 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
From: Richard Gobert <richardbgobert@gmail.com>
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Date: Wed, 3 Jan 2024 15:44:21 +0100
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Subject: [PATCH] net: gro: parse ipv6 ext headers without frag0 invalidation
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The existing code always pulls the IPv6 header and sets the transport
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offset initially. Then optionally again pulls any extension headers in
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ipv6_gso_pull_exthdrs and sets the transport offset again on return from
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that call. skb->data is set at the start of the first extension header
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before calling ipv6_gso_pull_exthdrs, and must disable the frag0
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optimization because that function uses pskb_may_pull/pskb_pull instead of
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skb_gro_ helpers. It sets the GRO offset to the TCP header with
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skb_gro_pull and sets the transport header. Then returns skb->data to its
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position before this block.
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This commit introduces a new helper function - ipv6_gro_pull_exthdrs -
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which is used in ipv6_gro_receive to pull ipv6 ext headers instead of
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ipv6_gso_pull_exthdrs. Thus, there is no modification of skb->data, all
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operations use skb_gro_* helpers, and the frag0 fast path can be taken for
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IPv6 packets with ext headers.
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Signed-off-by: Richard Gobert <richardbgobert@gmail.com>
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Reviewed-by: Willem de Bruijn <willemb@google.com>
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Reviewed-by: David Ahern <dsahern@kernel.org>
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Reviewed-by: Eric Dumazet <edumazet@google.com>
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Link: https://lore.kernel.org/r/504130f6-b56c-4dcc-882c-97942c59f5b7@gmail.com
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Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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---
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--- a/net/ipv6/ip6_offload.c
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+++ b/net/ipv6/ip6_offload.c
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@@ -36,6 +36,40 @@
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 		INDIRECT_CALL_L4(cb, f2, f1, head, skb);	\
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 })
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+static int ipv6_gro_pull_exthdrs(struct sk_buff *skb, int off, int proto)
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+{
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+	const struct net_offload *ops = NULL;
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+	struct ipv6_opt_hdr *opth;
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+
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+	for (;;) {
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+		int len;
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+
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+		ops = rcu_dereference(inet6_offloads[proto]);
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+
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+		if (unlikely(!ops))
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+			break;
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+
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+		if (!(ops->flags & INET6_PROTO_GSO_EXTHDR))
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+			break;
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+
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+		opth = skb_gro_header(skb, off + sizeof(*opth), off);
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+		if (unlikely(!opth))
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+			break;
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+
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+		len = ipv6_optlen(opth);
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+
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+		opth = skb_gro_header(skb, off + len, off);
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+		if (unlikely(!opth))
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+			break;
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+		proto = opth->nexthdr;
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+
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+		off += len;
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+	}
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+
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+	skb_gro_pull(skb, off - skb_network_offset(skb));
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+	return proto;
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+}
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+
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 static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto)
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 {
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 	const struct net_offload *ops = NULL;
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@@ -224,28 +258,25 @@ INDIRECT_CALLABLE_SCOPE struct sk_buff *
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 		goto out;
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 	skb_set_network_header(skb, off);
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-	skb_gro_pull(skb, sizeof(*iph));
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-	skb_set_transport_header(skb, skb_gro_offset(skb));
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-	flush += ntohs(iph->payload_len) != skb_gro_len(skb);
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+	flush += ntohs(iph->payload_len) != skb->len - hlen;
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 	proto = iph->nexthdr;
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 	ops = rcu_dereference(inet6_offloads[proto]);
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 	if (!ops || !ops->callbacks.gro_receive) {
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-		pskb_pull(skb, skb_gro_offset(skb));
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-		skb_gro_frag0_invalidate(skb);
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-		proto = ipv6_gso_pull_exthdrs(skb, proto);
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-		skb_gro_pull(skb, -skb_transport_offset(skb));
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-		skb_reset_transport_header(skb);
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-		__skb_push(skb, skb_gro_offset(skb));
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+		proto = ipv6_gro_pull_exthdrs(skb, hlen, proto);
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 		ops = rcu_dereference(inet6_offloads[proto]);
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 		if (!ops || !ops->callbacks.gro_receive)
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 			goto out;
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-		iph = ipv6_hdr(skb);
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+		iph = skb_gro_network_header(skb);
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+	} else {
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+		skb_gro_pull(skb, sizeof(*iph));
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 	}
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+	skb_set_transport_header(skb, skb_gro_offset(skb));
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+
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 	NAPI_GRO_CB(skb)->proto = proto;
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 	flush--;
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