From: Tobias Brunner <tobias@strongswan.org>
Date: Tue, 25 Mar 2025 12:44:44 +0000 (+0100)
Subject: kernel-netlink: Enable UDP GRO
X-Git-Tag: 6.0.2dr1~35
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=57e74f64b38f6f8a1c46f50a4c7660ed7dc77b61;p=thirdparty%2Fstrongswan.git

kernel-netlink: Enable UDP GRO

This enables GRO offload for inbound ESP-in-UDP packets if the
esp4|6_offload modules are loaded.  Note that inbound ESP or ESP-in-UDP
packets won't be visible on layer 3 in Netfilter or tcpdump.
---

diff --git a/src/include/linux/udp.h b/src/include/linux/udp.h
index b68a166f2e..c0920eaa2d 100644
--- a/src/include/linux/udp.h
+++ b/src/include/linux/udp.h
@@ -29,6 +29,7 @@ struct udphdr {
 /* UDP socket options */
 #define UDP_CORK	1	/* Never send partially complete segments */
 #define UDP_ENCAP	100	/* Set the socket to accept encapsulated packets */
+#define UDP_GRO		104	/* This socket can receive UDP GRO packets */
 
 /* UDP encapsulation types */
 #define UDP_ENCAP_ESPINUDP_NON_IKE	1 /* draft-ietf-ipsec-nat-t-ike-00/01 */
diff --git a/src/libcharon/plugins/kernel_netlink/kernel_netlink_ipsec.c b/src/libcharon/plugins/kernel_netlink/kernel_netlink_ipsec.c
index c6e50cc05d..df28228853 100644
--- a/src/libcharon/plugins/kernel_netlink/kernel_netlink_ipsec.c
+++ b/src/libcharon/plugins/kernel_netlink/kernel_netlink_ipsec.c
@@ -3884,6 +3884,12 @@ METHOD(kernel_ipsec_t, enable_udp_decap, bool,
 		DBG1(DBG_KNL, "unable to set UDP_ENCAP: %s", strerror(errno));
 		return FALSE;
 	}
+	type = 1;
+	if (setsockopt(fd, SOL_UDP, UDP_GRO, &type, sizeof(type)) < 0)
+	{
+		DBG1(DBG_KNL, "unable to set UDP_GRO: %s", strerror(errno));
+		return FALSE;
+	}
 	return TRUE;
 }