Commit cad052e6 authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

Merge branch 'net-remove-some-skb_mac_header-assumptions' 

Eric Dumazet says:

====================
net: remove some skb_mac_header assumptions

Historically, we tried o maintain skb_mac_header available in most of
networking paths.

When reaching ndo_start_xmit() handlers, skb_mac_header() should always
be skb->data.

With recent additions of skb_mac_header_was_set() and
DEBUG_NET_WARN_ON_ONCE() in skb_mac_header(), we can attempt
to remove our reliance on skb_mac_header in TX paths.

When this effort completes we will remove skb_reset_mac_header()
from __dev_queue_xmit() and replace it by
skb_unset_mac_header() on DEBUG_NET builds.
====================

Link: https://lore.kernel.org/r/20230321164519.1286357-1-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parents b50fea1f b3be9488

net/core/dev.c

+4 −4
Original line number Diff line number Diff line
@@ -3735,25 +3735,25 @@ static void qdisc_pkt_len_init(struct sk_buff *skb) 
	 * we add to pkt_len the headers size of all segments

	 */

	if (shinfo->gso_size && skb_transport_header_was_set(skb)) {

		unsigned int hdr_len;

		u16 gso_segs = shinfo->gso_segs;

		unsigned int hdr_len;



		/* mac layer + network layer */

		hdr_len = skb_transport_header(skb) - skb_mac_header(skb);

		hdr_len = skb_transport_offset(skb);



		/* + transport layer */

		if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))) {

			const struct tcphdr *th;

			struct tcphdr _tcphdr;



			th = skb_header_pointer(skb, skb_transport_offset(skb),

			th = skb_header_pointer(skb, hdr_len,

						sizeof(_tcphdr), &_tcphdr);

			if (likely(th))

				hdr_len += __tcp_hdrlen(th);

		} else {

			struct udphdr _udphdr;



			if (skb_header_pointer(skb, skb_transport_offset(skb),

			if (skb_header_pointer(skb, hdr_len,

					       sizeof(_udphdr), &_udphdr))

				hdr_len += sizeof(struct udphdr);

		}

net/sched/act_mirred.c

+1 −1
Original line number Diff line number Diff line
@@ -295,7 +295,7 @@ TC_INDIRECT_SCOPE int tcf_mirred_act(struct sk_buff *skb, 
	at_nh = skb->data == skb_network_header(skb);

	if (at_nh != expects_nh) {

		mac_len = skb_at_tc_ingress(skb) ? skb->mac_len :

			  skb_network_header(skb) - skb_mac_header(skb);

			  skb_network_offset(skb);

		if (expects_nh) {

			/* target device/action expect data at nh */

			skb_pull_rcsum(skb2, mac_len);

net/sched/act_mpls.c

+1 −1
Original line number Diff line number Diff line
@@ -69,7 +69,7 @@ TC_INDIRECT_SCOPE int tcf_mpls_act(struct sk_buff *skb, 
		skb_push_rcsum(skb, skb->mac_len);

		mac_len = skb->mac_len;

	} else {

		mac_len = skb_network_header(skb) - skb_mac_header(skb);

		mac_len = skb_network_offset(skb);

	}



	ret = READ_ONCE(m->tcf_action);

net/sched/sch_cake.c

+3 −3
Original line number Diff line number Diff line
@@ -1360,7 +1360,7 @@ static u32 cake_overhead(struct cake_sched_data *q, const struct sk_buff *skb) 
		return cake_calc_overhead(q, len, off);



	/* borrowed from qdisc_pkt_len_init() */

	hdr_len = skb_transport_header(skb) - skb_mac_header(skb);

	hdr_len = skb_transport_offset(skb);



	/* + transport layer */

	if (likely(shinfo->gso_type & (SKB_GSO_TCPV4 |
@@ -1368,14 +1368,14 @@ static u32 cake_overhead(struct cake_sched_data *q, const struct sk_buff *skb) 
		const struct tcphdr *th;

		struct tcphdr _tcphdr;



		th = skb_header_pointer(skb, skb_transport_offset(skb),

		th = skb_header_pointer(skb, hdr_len,

					sizeof(_tcphdr), &_tcphdr);

		if (likely(th))

			hdr_len += __tcp_hdrlen(th);

	} else {

		struct udphdr _udphdr;



		if (skb_header_pointer(skb, skb_transport_offset(skb),

		if (skb_header_pointer(skb, hdr_len,

				       sizeof(_udphdr), &_udphdr))

			hdr_len += sizeof(struct udphdr);

	}