From nobody Sun Feb 8 05:12:58 2026 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4E309331202 for ; Mon, 19 Jan 2026 05:40:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768801261; cv=none; b=CABiaTRlhqs8yhEtUyMo5ppFWrQkHYCPPd4mpQDQAWm0vRVAw6k9y0L0V0CyVTZ/pKW2LjiIxcd81U4CQmrtxJfM+UzJAzHdoZ54ORX8JZPn+E6jmafoIuf6hMaddKmG8iPCknQMM8g8sFF+S9r7pVPYsBFdUp3Va3z1OY0CT70= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768801261; c=relaxed/simple; bh=j88S8UVMF4UN7ODSbM06V5kHCjacP62bjwVGVI7CEOg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=AkHbEuPqVm/tRugKN62omaJLNtFr+SsDsC8uDQv41xZ6oT/Rx9kLyLC2ELFE9k98u43VSRgvz0lavSR6a9HFlqHiECU6TRt06huCi/vjyxP/cpklgrLUc7ZaN0rW9q6wc2FsnJeglNCVWOdPnWjcpK6KYgElTCglZZuMQMWrUUY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=IWRp6qhT; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="IWRp6qhT" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1768801255; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=WvZgwvJeGyGBpLubrY0OttguapRc1gPc0WNHWvn2/cU=; b=IWRp6qhTJSugoQq3vnoYwz14SIxwBvrXDnttnQ2zyrmw6E0PKlfvE1Qzj92n0tyTM5H4Mf eC43i+ZRNmfh2hlCwJk9BdormBO8PlRDBYikv0IiD72nqnp+q8C+ItvBQ0O8d+Pflz+RXy q0cLJsZ6kJqKtNmwcJ5slTi0dOmmavs= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-313-RubMhR79MlerTRDX_QIAEg-1; Mon, 19 Jan 2026 00:40:53 -0500 X-MC-Unique: RubMhR79MlerTRDX_QIAEg-1 X-Mimecast-MFC-AGG-ID: RubMhR79MlerTRDX_QIAEg_1768801252 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id F36131956080; Mon, 19 Jan 2026 05:40:51 +0000 (UTC) Received: from xudu-thinkpadx1carbongen9.nay.csb (unknown [10.72.116.28]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id CD5A718004D8; Mon, 19 Jan 2026 05:40:45 +0000 (UTC) From: Xu Du To: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, shuah@kernel.org Cc: netdev@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next v5 4/7] selftest: tun: Add helpers for GSO over UDP tunnel Date: Mon, 19 Jan 2026 13:40:01 +0800 Message-ID: In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Content-Type: text/plain; charset="utf-8" In preparation for testing GSO over UDP tunnels, enhance the test infrastructure to support a more complex data path involving a TUN device and a GENEVE udp tunnel. This patch introduces a dedicated setup/teardown topology that creates both a GENEVE tunnel interface and a TUN interface. The TUN device acts as the VTEP (Virtual Tunnel Endpoint), allowing it to send and receive virtio-net packets. This setup effectively tests the kernel's data path for encapsulated traffic. Note that after adding a new address to the UDP tunnel, we need to wait a bit until the associated route is available. Additionally, a new data structure is defined to manage test parameters. This structure is designed to be extensible, allowing different test data and configurations to be easily added in subsequent patches. Signed-off-by: Xu Du --- v4 -> v5: - Use Geneve instead of VXLAN due to missing YNL support. v1 -> v2: - Explicitly wait for successful target route lookup before transmitting the packets. - Add UDP connect() to verify remote reachability. - Abstract address assignment logic into helpers. tools/testing/selftests/net/tun.c | 425 ++++++++++++++++++++++++++++++ 1 file changed, 425 insertions(+) diff --git a/tools/testing/selftests/net/tun.c b/tools/testing/selftests/ne= t/tun.c index d9030bdd2e06..ec089355312b 100644 --- a/tools/testing/selftests/net/tun.c +++ b/tools/testing/selftests/net/tun.c @@ -15,6 +15,80 @@ #include "kselftest_harness.h" #include "tuntap_helpers.h" =20 +static const char param_dev_geneve_name[] =3D "geneve1"; +static unsigned char param_hwaddr_outer_dst[] =3D { 0x00, 0xfe, 0x98, + 0x14, 0x22, 0x42 }; +static unsigned char param_hwaddr_outer_src[] =3D { 0x00, 0xfe, 0x98, + 0x94, 0xd2, 0x43 }; +static unsigned char param_hwaddr_inner_dst[] =3D { 0x00, 0xfe, 0x98, + 0x94, 0x22, 0xcc }; +static unsigned char param_hwaddr_inner_src[] =3D { 0x00, 0xfe, 0x98, + 0x94, 0xd2, 0xdd }; + +static struct in_addr param_ipaddr4_outer_dst =3D { + __constant_htonl(0xac100001), +}; + +static struct in_addr param_ipaddr4_outer_src =3D { + __constant_htonl(0xac100002), +}; + +static struct in_addr param_ipaddr4_inner_dst =3D { + __constant_htonl(0xac100101), +}; + +static struct in_addr param_ipaddr4_inner_src =3D { + __constant_htonl(0xac100102), +}; + +static struct in6_addr param_ipaddr6_outer_dst =3D { + { { 0x20, 0x02, 0x0d, 0xb8, 0x01, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 } }, +}; + +static struct in6_addr param_ipaddr6_outer_src =3D { + { { 0x20, 0x02, 0x0d, 0xb8, 0x01, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2 } }, +}; + +static struct in6_addr param_ipaddr6_inner_dst =3D { + { { 0x20, 0x02, 0x0d, 0xb8, 0x02, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 } }, +}; + +static struct in6_addr param_ipaddr6_inner_src =3D { + { { 0x20, 0x02, 0x0d, 0xb8, 0x02, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2 } }, +}; + +#define VN_ID 1 +#define VN_PORT 4789 +#define UDP_SRC_PORT 22 +#define UDP_DST_PORT 48878 +#define IPPREFIX_LEN 24 +#define IP6PREFIX_LEN 64 +#define TIMEOUT_SEC 10 +#define TIMEOUT_USEC 100000 +#define MAX_RETRIES 20 + +#define UDP_TUNNEL_GENEVE_4IN4 0x01 +#define UDP_TUNNEL_GENEVE_6IN4 0x02 +#define UDP_TUNNEL_GENEVE_4IN6 0x04 +#define UDP_TUNNEL_GENEVE_6IN6 0x08 + +#define UDP_TUNNEL_OUTER_IPV4 (UDP_TUNNEL_GENEVE_4IN4 | UDP_TUNNEL_GENEVE_= 6IN4) +#define UDP_TUNNEL_INNER_IPV4 (UDP_TUNNEL_GENEVE_4IN4 | UDP_TUNNEL_GENEVE_= 4IN6) + +#define TUN_VNET_TNL_SIZE sizeof(struct virtio_net_hdr_v1_hash_tunnel) + +struct geneve_setup_config { + int family; + union { + struct in_addr r4; + struct in6_addr r6; + } remote; + __be32 vnid; + __be16 vnport; + unsigned char hwaddr[6]; + uint8_t csum; +}; + static int tun_attach(int fd, char *dev) { struct ifreq ifr; @@ -67,6 +141,202 @@ static int tun_delete(char *dev) return ip_link_del(dev); } =20 +static int tun_open(char *dev, const int flags, const int hdrlen, + const int features, const unsigned char *mac_addr) +{ + struct ifreq ifr =3D { 0 }; + int fd, sk =3D -1; + + fd =3D open("/dev/net/tun", O_RDWR); + if (fd < 0) { + perror("open"); + return -1; + } + + ifr.ifr_flags =3D flags; + if (ioctl(fd, TUNSETIFF, (void *)&ifr) < 0) { + perror("ioctl(TUNSETIFF)"); + goto err; + } + strcpy(dev, ifr.ifr_name); + + if (hdrlen > 0) { + if (ioctl(fd, TUNSETVNETHDRSZ, &hdrlen) < 0) { + perror("ioctl(TUNSETVNETHDRSZ)"); + goto err; + } + } + + if (features) { + if (ioctl(fd, TUNSETOFFLOAD, features) < 0) { + perror("ioctl(TUNSETOFFLOAD)"); + goto err; + } + } + + sk =3D socket(PF_INET, SOCK_DGRAM, 0); + if (sk < 0) { + perror("socket"); + goto err; + } + + if (ioctl(sk, SIOCGIFFLAGS, &ifr) < 0) { + perror("ioctl(SIOCGIFFLAGS)"); + goto err; + } + + ifr.ifr_flags |=3D (IFF_UP | IFF_RUNNING); + if (ioctl(sk, SIOCSIFFLAGS, &ifr) < 0) { + perror("ioctl(SIOCSIFFLAGS)"); + goto err; + } + + if (mac_addr && flags & IFF_TAP) { + ifr.ifr_hwaddr.sa_family =3D ARPHRD_ETHER; + memcpy(ifr.ifr_hwaddr.sa_data, mac_addr, ETH_ALEN); + + if (ioctl(sk, SIOCSIFHWADDR, &ifr) < 0) { + perror("ioctl(SIOCSIFHWADDR)"); + goto err; + } + } + +out: + if (sk >=3D 0) + close(sk); + return fd; + +err: + close(fd); + fd =3D -1; + goto out; +} + +static size_t sockaddr_len(int family) +{ + return (family =3D=3D AF_INET) ? sizeof(struct sockaddr_in) : + sizeof(struct sockaddr_in6); +} + +static int geneve_fill_newlink(struct rt_link_newlink_req *req, void *data) +{ + struct geneve_setup_config *cfg =3D data; + +#define SET_GENEVE_REMOTE rt_link_newlink_req_set_linkinfo_data_geneve_rem= ote +#define SET_GENEVE_REMOTE6 rt_link_newlink_req_set_linkinfo_data_geneve_re= mote6 + + rt_link_newlink_req_set_address(req, cfg->hwaddr, ETH_ALEN); + rt_link_newlink_req_set_linkinfo_data_geneve_id(req, cfg->vnid); + rt_link_newlink_req_set_linkinfo_data_geneve_port(req, cfg->vnport); + rt_link_newlink_req_set_linkinfo_data_geneve_udp_csum(req, cfg->csum); + + if (cfg->family =3D=3D AF_INET) + SET_GENEVE_REMOTE(req, cfg->remote.r4.s_addr); + else + SET_GENEVE_REMOTE6(req, &cfg->remote.r6, + sizeof(cfg->remote.r6)); + + return 0; +} + +static int geneve_create(const char *dev, int family, void *remote, + void *hwaddr) +{ + struct geneve_setup_config geneve; + + memset(&geneve, 0, sizeof(geneve)); + geneve.vnid =3D VN_ID; + geneve.vnport =3D htons(VN_PORT); + geneve.csum =3D 1; + geneve.family =3D family; + if (family =3D=3D AF_INET) + memcpy(&geneve.remote.r4, remote, sizeof(struct in_addr)); + else + memcpy(&geneve.remote.r6, remote, sizeof(struct in6_addr)); + memcpy(geneve.hwaddr, hwaddr, ETH_ALEN); + + return ip_link_add(dev, "geneve", geneve_fill_newlink, (void *)&geneve); +} + +static int set_pmtu_discover(int fd, bool is_ipv4) +{ + int level, name, val; + + if (is_ipv4) { + level =3D SOL_IP; + name =3D IP_MTU_DISCOVER; + val =3D IP_PMTUDISC_DO; + } else { + level =3D SOL_IPV6; + name =3D IPV6_MTU_DISCOVER; + val =3D IPV6_PMTUDISC_DO; + } + + return setsockopt(fd, level, name, &val, sizeof(val)); +} + +static int udp_socket_open(struct sockaddr_storage *ssa, bool do_frag, + bool do_connect, struct sockaddr_storage *dsa) +{ + struct timeval to =3D { .tv_sec =3D TIMEOUT_SEC }; + int fd, family =3D ssa->ss_family; + int salen =3D sockaddr_len(family); + + fd =3D socket(family, SOCK_DGRAM, 0); + if (fd < 0) + return -1; + + if (bind(fd, (struct sockaddr *)ssa, salen) < 0) { + perror("bind"); + goto err; + } + + if (do_connect && connect(fd, (struct sockaddr *)dsa, salen) < 0) { + perror("connect"); + goto err; + } + + if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &to, sizeof(to)) < 0) { + perror("setsockopt(SO_RCVTIMEO)"); + goto err; + } + + if (!do_frag && set_pmtu_discover(fd, family =3D=3D AF_INET) < 0) { + perror("set_pmtu_discover"); + goto err; + } + return fd; + +err: + close(fd); + return -1; +} + +static void parse_route_rsp(struct rt_route_getroute_rsp *rsp, void *rtm_t= ype) +{ + *(uint8_t *)rtm_type =3D rsp->_hdr.rtm_type; +} + +static int ip_route_check(const char *intf, int family, void *addr) +{ + uint8_t rtm_type, table =3D RT_TABLE_LOCAL; + int retries =3D MAX_RETRIES; + + while (retries-- > 0) { + if (ip_route_get(intf, family, table, addr, parse_route_rsp, + &rtm_type) =3D=3D 0 && + rtm_type =3D=3D RTN_LOCAL) + break; + + usleep(TIMEOUT_USEC); + } + + if (retries < 0) + return -1; + + return 0; +} + FIXTURE(tun) { char ifname[IFNAMSIZ]; @@ -129,4 +399,159 @@ TEST_F(tun, reattach_close_delete) EXPECT_EQ(tun_delete(self->ifname), 0); } =20 +FIXTURE(tun_vnet_udptnl) +{ + char ifname[IFNAMSIZ]; + int fd, sock; +}; + +FIXTURE_VARIANT(tun_vnet_udptnl) +{ + int tunnel_type; + bool is_tap; +}; + +/* clang-format off */ +#define TUN_VNET_UDPTNL_VARIANT_ADD(type, desc) = \ + FIXTURE_VARIANT_ADD(tun_vnet_udptnl, desc##udptnl) { \ + .tunnel_type =3D type, \ + .is_tap =3D true, \ + } +/* clang-format on */ + +TUN_VNET_UDPTNL_VARIANT_ADD(UDP_TUNNEL_GENEVE_4IN4, 4in4); +TUN_VNET_UDPTNL_VARIANT_ADD(UDP_TUNNEL_GENEVE_6IN4, 6in4); +TUN_VNET_UDPTNL_VARIANT_ADD(UDP_TUNNEL_GENEVE_4IN6, 4in6); +TUN_VNET_UDPTNL_VARIANT_ADD(UDP_TUNNEL_GENEVE_6IN6, 6in6); + +static void assign_ifaddr_vars(int family, int is_outer, void **srcip, + void **dstip, void **srcmac, void **dstmac) +{ + if (is_outer) { + if (family =3D=3D AF_INET) { + *srcip =3D (void *)¶m_ipaddr4_outer_src; + *dstip =3D (void *)¶m_ipaddr4_outer_dst; + } else { + *srcip =3D (void *)¶m_ipaddr6_outer_src; + *dstip =3D (void *)¶m_ipaddr6_outer_dst; + } + *srcmac =3D param_hwaddr_outer_src; + *dstmac =3D param_hwaddr_outer_dst; + } else { + if (family =3D=3D AF_INET) { + *srcip =3D (void *)¶m_ipaddr4_inner_src; + *dstip =3D (void *)¶m_ipaddr4_inner_dst; + } else { + *srcip =3D (void *)¶m_ipaddr6_inner_src; + *dstip =3D (void *)¶m_ipaddr6_inner_dst; + } + *srcmac =3D param_hwaddr_inner_src; + *dstmac =3D param_hwaddr_inner_dst; + } +} + +static void assign_sockaddr_vars(int family, int is_outer, + struct sockaddr_storage *src, + struct sockaddr_storage *dst) +{ + src->ss_family =3D family; + dst->ss_family =3D family; + + if (family =3D=3D AF_INET) { + struct sockaddr_in *s4 =3D (struct sockaddr_in *)src; + struct sockaddr_in *d4 =3D (struct sockaddr_in *)dst; + + s4->sin_addr =3D is_outer ? param_ipaddr4_outer_src : + param_ipaddr4_inner_src; + d4->sin_addr =3D is_outer ? param_ipaddr4_outer_dst : + param_ipaddr4_inner_dst; + if (!is_outer) { + s4->sin_port =3D htons(UDP_SRC_PORT); + d4->sin_port =3D htons(UDP_DST_PORT); + } + } else { + struct sockaddr_in6 *s6 =3D (struct sockaddr_in6 *)src; + struct sockaddr_in6 *d6 =3D (struct sockaddr_in6 *)dst; + + s6->sin6_addr =3D is_outer ? param_ipaddr6_outer_src : + param_ipaddr6_inner_src; + d6->sin6_addr =3D is_outer ? param_ipaddr6_outer_dst : + param_ipaddr6_inner_dst; + if (!is_outer) { + s6->sin6_port =3D htons(UDP_SRC_PORT); + d6->sin6_port =3D htons(UDP_DST_PORT); + } + } +} + +FIXTURE_SETUP(tun_vnet_udptnl) +{ + int ret, family, prefix, flags, features; + int tunnel_type =3D variant->tunnel_type; + struct sockaddr_storage ssa, dsa; + void *sip, *dip, *smac, *dmac; + + flags =3D (variant->is_tap ? IFF_TAP : IFF_TUN) | IFF_VNET_HDR | + IFF_MULTI_QUEUE | IFF_NO_PI; + features =3D TUN_F_CSUM | TUN_F_UDP_TUNNEL_GSO | + TUN_F_UDP_TUNNEL_GSO_CSUM | TUN_F_USO4 | TUN_F_USO6; + self->fd =3D tun_open(self->ifname, flags, TUN_VNET_TNL_SIZE, features, + param_hwaddr_outer_src); + ASSERT_GE(self->fd, 0); + + family =3D (tunnel_type & UDP_TUNNEL_OUTER_IPV4) ? AF_INET : AF_INET6; + prefix =3D (family =3D=3D AF_INET) ? IPPREFIX_LEN : IP6PREFIX_LEN; + assign_ifaddr_vars(family, 1, &sip, &dip, &smac, &dmac); + + ret =3D ip_addr_add(self->ifname, family, sip, prefix); + ASSERT_EQ(ret, 0); + ret =3D ip_neigh_add(self->ifname, family, dip, dmac); + ASSERT_EQ(ret, 0); + ret =3D ip_route_check(self->ifname, family, sip); + ASSERT_EQ(ret, 0); + + ret =3D geneve_create(param_dev_geneve_name, family, dip, + param_hwaddr_inner_src); + ASSERT_EQ(ret, 0); + + family =3D (tunnel_type & UDP_TUNNEL_INNER_IPV4) ? AF_INET : AF_INET6; + prefix =3D (family =3D=3D AF_INET) ? IPPREFIX_LEN : IP6PREFIX_LEN; + assign_ifaddr_vars(family, 0, &sip, &dip, &smac, &dmac); + + ret =3D ip_addr_add(param_dev_geneve_name, family, sip, prefix); + ASSERT_EQ(ret, 0); + ret =3D ip_neigh_add(param_dev_geneve_name, family, dip, dmac); + ASSERT_EQ(ret, 0); + ret =3D ip_route_check(param_dev_geneve_name, family, sip); + ASSERT_EQ(ret, 0); + + assign_sockaddr_vars(family, 0, &ssa, &dsa); + self->sock =3D udp_socket_open(&ssa, false, true, &dsa); + ASSERT_GE(self->sock, 0); +} + +FIXTURE_TEARDOWN(tun_vnet_udptnl) +{ + int ret; + + if (self->sock !=3D -1) + close(self->sock); + + ret =3D ip_link_del(param_dev_geneve_name); + EXPECT_EQ(ret, 0); + + ret =3D tun_delete(self->ifname); + EXPECT_EQ(ret, 0); +} + +TEST_F(tun_vnet_udptnl, basic) +{ + int ret; + char cmd[256] =3D { 0 }; + + sprintf(cmd, "ip addr show %s > /dev/null 2>&1", param_dev_geneve_name); + ret =3D system(cmd); + ASSERT_EQ(ret, 0); +} + TEST_HARNESS_MAIN --=20 2.49.0