Commit db2dede2 authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

Merge branch 'lift-udp_segment-restriction-for-egress-via-device-w-o-csum-offload' 

Jakub Sitnicki says:

====================
Lift UDP_SEGMENT restriction for egress via device w/o csum offload

This is a follow-up to an earlier question [1] if we can make UDP GSO work
with any egress device, even those with no checksum offload capability.
That's the default setup for TUN/TAP.

Because there is a change in behavior - sendmsg() does no longer return
EIO error - I'm submitting through net-next tree, rather than net,
as per Willem's advice.

[1] https://lore.kernel.org/netdev/87jzqsld6q.fsf@cloudflare.com/

v1: https://lore.kernel.org/r/20240622-linux-udpgso-v1-0-d2344157ab2a@cloudflare.com
====================

Link: https://patch.msgid.link/20240626-linux-udpgso-v2-0-422dfcbd6b48@cloudflare.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parents 748e3bbf 3e400219

net/ipv4/udp.c

+1 −2
Original line number Diff line number Diff line
@@ -938,8 +938,7 @@ static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4, 
			kfree_skb(skb);

			return -EINVAL;

		}

		if (skb->ip_summed != CHECKSUM_PARTIAL || is_udplite ||

		    dst_xfrm(skb_dst(skb))) {

		if (is_udplite || dst_xfrm(skb_dst(skb))) {

			kfree_skb(skb);

			return -EIO;

		}

net/ipv4/udp_offload.c

+8 −0
Original line number Diff line number Diff line
@@ -357,6 +357,14 @@ struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb, 
	else

		uh->check = gso_make_checksum(seg, ~check) ? : CSUM_MANGLED_0;



	/* On the TX path, CHECKSUM_NONE and CHECKSUM_UNNECESSARY have the same

	 * meaning. However, check for bad offloads in the GSO stack expects the

	 * latter, if the checksum was calculated in software. To vouch for the

	 * segment skbs we actually need to set it on the gso_skb.

	 */

	if (gso_skb->ip_summed == CHECKSUM_NONE)

		gso_skb->ip_summed = CHECKSUM_UNNECESSARY;



	/* update refcount for the packet */

	if (copy_dtor) {

		int delta = sum_truesize - gso_skb->truesize;

net/ipv6/udp.c

+1 −2
Original line number Diff line number Diff line
@@ -1257,8 +1257,7 @@ static int udp_v6_send_skb(struct sk_buff *skb, struct flowi6 *fl6, 
			kfree_skb(skb);

			return -EINVAL;

		}

		if (skb->ip_summed != CHECKSUM_PARTIAL || is_udplite ||

		    dst_xfrm(skb_dst(skb))) {

		if (is_udplite || dst_xfrm(skb_dst(skb))) {

			kfree_skb(skb);

			return -EIO;

		}

tools/testing/selftests/net/udpgso.c

+12 −3
Original line number Diff line number Diff line
@@ -53,6 +53,7 @@ static bool cfg_do_ipv6; 
static bool		cfg_do_connected;

static bool		cfg_do_connectionless;

static bool		cfg_do_msgmore;

static bool		cfg_do_recv = true;

static bool		cfg_do_setsockopt;

static int		cfg_specific_test_id = -1;
@@ -414,6 +415,9 @@ static void run_one(struct testcase *test, int fdt, int fdr, 
	if (!sent)

		return;



	if (!cfg_do_recv)

		return;



	if (test->gso_len)

		mss = test->gso_len;

	else
@@ -464,8 +468,10 @@ static void run_test(struct sockaddr *addr, socklen_t alen) 
	if (fdr == -1)

		error(1, errno, "socket r");



	if (cfg_do_recv) {

		if (bind(fdr, addr, alen))

			error(1, errno, "bind");

	}



	/* Have tests fail quickly instead of hang */

	if (setsockopt(fdr, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)))
@@ -524,7 +530,7 @@ static void parse_opts(int argc, char **argv) 
{

	int c;



	while ((c = getopt(argc, argv, "46cCmst:")) != -1) {

	while ((c = getopt(argc, argv, "46cCmRst:")) != -1) {

		switch (c) {

		case '4':

			cfg_do_ipv4 = true;
@@ -541,6 +547,9 @@ static void parse_opts(int argc, char **argv) 
		case 'm':

			cfg_do_msgmore = true;

			break;

		case 'R':

			cfg_do_recv = false;

			break;

		case 's':

			cfg_do_setsockopt = true;

			break;

tools/testing/selftests/net/udpgso.sh

+43 −0
Original line number Diff line number Diff line
@@ -27,6 +27,31 @@ test_route_mtu() { 
	ip route add local fd00::1/128 table local dev lo mtu 1500

}



setup_dummy_sink() {

	ip link add name sink mtu 1500 type dummy

	ip addr add dev sink 10.0.0.0/24

	ip addr add dev sink fd00::2/64 nodad

	ip link set dev sink up

}



test_hw_gso_hw_csum() {

	setup_dummy_sink

	ethtool -K sink tx-checksum-ip-generic on >/dev/null

	ethtool -K sink tx-udp-segmentation on >/dev/null

}



test_sw_gso_hw_csum() {

	setup_dummy_sink

	ethtool -K sink tx-checksum-ip-generic on >/dev/null

	ethtool -K sink tx-udp-segmentation off >/dev/null

}



test_sw_gso_sw_csum() {

	setup_dummy_sink

	ethtool -K sink tx-checksum-ip-generic off >/dev/null

	ethtool -K sink tx-udp-segmentation off >/dev/null

}



if [ "$#" -gt 0 ]; then

	"$1"

	shift 2 # pop "test_*" arg and "--" delimiter
@@ -56,3 +81,21 @@ echo "ipv4 msg_more" 


echo "ipv6 msg_more"

./in_netns.sh "$0" test_dev_mtu -- ./udpgso -6 -C -m



echo "ipv4 hw-gso hw-csum"

./in_netns.sh "$0" test_hw_gso_hw_csum -- ./udpgso -4 -C -R



echo "ipv6 hw-gso hw-csum"

./in_netns.sh "$0" test_hw_gso_hw_csum -- ./udpgso -6 -C -R



echo "ipv4 sw-gso hw-csum"

./in_netns.sh "$0" test_sw_gso_hw_csum -- ./udpgso -4 -C -R



echo "ipv6 sw-gso hw-csum"

./in_netns.sh "$0" test_sw_gso_hw_csum -- ./udpgso -6 -C -R



echo "ipv4 sw-gso sw-csum"

./in_netns.sh "$0" test_sw_gso_sw_csum -- ./udpgso -4 -C -R



echo "ipv6 sw-gso sw-csum"

./in_netns.sh "$0" test_sw_gso_sw_csum -- ./udpgso -6 -C -R