diff options
Diffstat (limited to 'queue-6.6/net-change-maximum-number-of-udp-segments-to-128.patch')
| -rw-r--r-- | queue-6.6/net-change-maximum-number-of-udp-segments-to-128.patch | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/queue-6.6/net-change-maximum-number-of-udp-segments-to-128.patch b/queue-6.6/net-change-maximum-number-of-udp-segments-to-128.patch new file mode 100644 index 0000000000..5ae5229fa2 --- /dev/null +++ b/queue-6.6/net-change-maximum-number-of-udp-segments-to-128.patch @@ -0,0 +1,71 @@ +From 4f092dadde909f1ea6e3b40285926f23455fc2b7 Mon Sep 17 00:00:00 2001 +From: Sasha Levin <sashal@kernel.org> +Date: Thu, 11 Apr 2024 08:11:24 +0300 +Subject: net: change maximum number of UDP segments to 128 + +From: Yuri Benditovich <yuri.benditovich@daynix.com> + +[ Upstream commit 1382e3b6a3500c245e5278c66d210c02926f804f ] + +The commit fc8b2a619469 +("net: more strict VIRTIO_NET_HDR_GSO_UDP_L4 validation") +adds check of potential number of UDP segments vs +UDP_MAX_SEGMENTS in linux/virtio_net.h. +After this change certification test of USO guest-to-guest +transmit on Windows driver for virtio-net device fails, +for example with packet size of ~64K and mss of 536 bytes. +In general the USO should not be more restrictive than TSO. +Indeed, in case of unreasonably small mss a lot of segments +can cause queue overflow and packet loss on the destination. +Limit of 128 segments is good for any practical purpose, +with minimal meaningful mss of 536 the maximal UDP packet will +be divided to ~120 segments. +The number of segments for UDP packets is validated vs +UDP_MAX_SEGMENTS also in udp.c (v4,v6), this does not affect +quest-to-guest path but does affect packets sent to host, for +example. +It is important to mention that UDP_MAX_SEGMENTS is kernel-only +define and not available to user mode socket applications. +In order to request MSS smaller than MTU the applications +just uses setsockopt with SOL_UDP and UDP_SEGMENT and there is +no limitations on socket API level. + +Fixes: fc8b2a619469 ("net: more strict VIRTIO_NET_HDR_GSO_UDP_L4 validation") +Signed-off-by: Yuri Benditovich <yuri.benditovich@daynix.com> +Reviewed-by: Willem de Bruijn <willemb@google.com> +Signed-off-by: David S. Miller <davem@davemloft.net> +Signed-off-by: Sasha Levin <sashal@kernel.org> +--- + include/linux/udp.h | 2 +- + tools/testing/selftests/net/udpgso.c | 2 +- + 2 files changed, 2 insertions(+), 2 deletions(-) + +diff --git a/include/linux/udp.h b/include/linux/udp.h +index 94e63b2695406..00790bb5cbde6 100644 +--- a/include/linux/udp.h ++++ b/include/linux/udp.h +@@ -105,7 +105,7 @@ struct udp_sock { + #define udp_assign_bit(nr, sk, val) \ + assign_bit(UDP_FLAGS_##nr, &udp_sk(sk)->udp_flags, val) + +-#define UDP_MAX_SEGMENTS (1 << 6UL) ++#define UDP_MAX_SEGMENTS (1 << 7UL) + + #define udp_sk(ptr) container_of_const(ptr, struct udp_sock, inet.sk) + +diff --git a/tools/testing/selftests/net/udpgso.c b/tools/testing/selftests/net/udpgso.c +index 7badaf215de28..b02080d09fbc0 100644 +--- a/tools/testing/selftests/net/udpgso.c ++++ b/tools/testing/selftests/net/udpgso.c +@@ -34,7 +34,7 @@ + #endif + + #ifndef UDP_MAX_SEGMENTS +-#define UDP_MAX_SEGMENTS (1 << 6UL) ++#define UDP_MAX_SEGMENTS (1 << 7UL) + #endif + + #define CONST_MTU_TEST 1500 +-- +2.43.0 + |