From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=95.215.58.111 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794302696; b=rhwyPdPOEwpg7C6/nGsR7I6lHg2JjrHqao97joScuHni2iQu9Vcc85SSnku4wR689DoO 1yj3YtUVhz4I9oY9d1s0vUW5BKufrXPnW+wFw/n61HSsbT4mXoOoQgVN4kY873sAVSAu6 URTq4AS+fHekoXsUWtR9ZHdfCiU2HM11GGG8OdFGpjfBkilwVY3EHref2mOX23UCBb5qq YXWw5kimR9IQYw8klJlgSKABLkQkb0aIF+hGgC8HnhbZg+9NIoZsp4rQw6iAL4zMqTMtf FZxcqmwawo8EI1ovjSo5umaajJU/9WRyvQVKZZFNJuk9xV1dnwJZgP6rSF4xdg533PQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794302696; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=g59WXbMEVAC+rwbfPbusgYn9rCMYzsS/Ea1X6BmPoQk=; b=g+VhfphjRTSno8RNChgKlrdJ4cjyFVGVltjdWYt5ioJ+SeRtqVvUOvHA1CueYiS+ycAp nUxDaI2x2bE7bdn/K4ve0VmUlwbp6Vm56MLq9Z14w7+WRZDlplmt1Alz4gntTAmXbwSV7 zVbHZ/ttfS/heQA58ua6KYPWPh/c/bBr0hVmrtJdajKaQ3VJo/N03njzloBAO4vl0CDbq WuTD+KN9v8QFDPQHUsj5lbQiAnQmY91qaOlBuPII6Ssrz6rpB25M2LLO4acchXvH6tap0 KUyxAtX9jQmWQCcr6ZDEDhtvdCxHQI7vetV2BHkPgOWpygmWkFnCJ4se6J3nF32rVeQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=jsjkEliL; arc=none smtp.remote-ip=95.215.58.111 Received: from mta1.migadu.com (out-111.mta1.migadu.com [95.215.58.111]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CEDAA6070FE5 for ; Tue, 10 Nov 2026 09:24:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org CEDAA6070FE5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=jsjkEliL X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=NrDs8IswZxyvOKP1XWG0B7QQ4QtrBkDyBDj9/5w4lmc=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1794302693; v=1; x=1794907493; b=jsjkEliLZ/+yssR9wR9O/Lh9syF0w9ilKzRDQ5vPbWVYAWBOdZ+G3T6Qfc8chLQrangeWieq 30du1DjzhNlX++VixVcv2j7Ywd0tph/Y+PoVDz0n+z7kgCx/cYcW2Pv544dHzbVSvfGon63eIdY LOiAAoL6HgjOZoCKHUf9URdE= X-Envelope-To: linux-kernel@vger.kernel.org Received: by mta12.migadu.com with ESMTPS id 1ee9f6a1fae2868a; Tue, 10 Nov 2026 09:24:52 +0000 X-Mizu-Trace-ID: 1ee9f6a1fae2868a X-Migadu-Flow: FLOW_OUT Date: Tue, 10 Nov 2026 17:24:33 +0800 From: Hangbin Liu To: Stephen Hemminger Cc: netdev@vger.kernel.org, dsahern@kernel.org, "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Shuah Khan , "open list:KERNEL SELFTEST FRAMEWORK" , open list Subject: Re: [PATCH 3/3] selftests: net: netlink-dumps: test dump of route larger than skb Message-ID: References: <20261109012115.11898-1-stephen@networkplumber.org> <20261109012115.11898-4-stephen@networkplumber.org> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261109012115.11898-4-stephen@networkplumber.org> On Sun, Nov 08, 2026 at 05:13:14PM -0800, Stephen Hemminger wrote: > Add IPv4 and IPv6 multipath routes that do not fit in the first dump > skb of a fresh socket. The dump must return the route or fail with > -EMSGSIZE, not end with status 0. > > IPv6 nexthops cannot use lo, so create a dummy device and generalize > lo_set_up() to if_set_up(). Add the IPv4 routing options to config. > > Assisted-by: Claude:claude-opus-5-5 > Signed-off-by: Stephen Hemminger > --- > tools/testing/selftests/net/config | 3 + > tools/testing/selftests/net/netlink-dumps.c | 271 +++++++++++++++++++- > 2 files changed, 270 insertions(+), 4 deletions(-) > > diff --git a/tools/testing/selftests/net/config b/tools/testing/selftests/net/config > index d4416f8bdcfd..e2f136274e6d 100644 > --- a/tools/testing/selftests/net/config > +++ b/tools/testing/selftests/net/config > @@ -29,6 +29,8 @@ CONFIG_IP6_NF_MATCH_RPFILTER=m > CONFIG_IP6_NF_NAT=m > CONFIG_IP6_NF_RAW=m > CONFIG_IP6_NF_TARGET_REJECT=m > +CONFIG_IP_ADVANCED_ROUTER=y > +CONFIG_IP_MULTIPLE_TABLES=y > CONFIG_IP_NF_FILTER=m > CONFIG_IP_NF_IPTABLES=m > CONFIG_IP_NF_IPTABLES_LEGACY=m > @@ -38,6 +40,7 @@ CONFIG_IP_NF_NAT=m > CONFIG_IP_NF_RAW=m > CONFIG_IP_NF_TARGET_REJECT=m > CONFIG_IP_NF_TARGET_TTL=m > +CONFIG_IP_ROUTE_MULTIPATH=y > CONFIG_IP_SCTP=m > CONFIG_IPV6=y > CONFIG_IPV6_FOU=m > diff --git a/tools/testing/selftests/net/netlink-dumps.c b/tools/testing/selftests/net/netlink-dumps.c > index 4a94a25167e2..43f63f3f2289 100644 > --- a/tools/testing/selftests/net/netlink-dumps.c > +++ b/tools/testing/selftests/net/netlink-dumps.c > @@ -263,11 +263,11 @@ TEST(close_with_ref) > usleep(100 * 1000); > } > > -static int lo_set_up(int sock, bool up) > +static int if_set_up(int sock, const char *name, bool up) > { > struct ifreq ifr = {}; > > - strcpy(ifr.ifr_name, "lo"); > + strcpy(ifr.ifr_name, name); > if (ioctl(sock, SIOCGIFFLAGS, &ifr)) > return -1; > if (up) > @@ -321,12 +321,12 @@ TEST(dump_with_queued_ntf) > sizeof(addr)), 0); > > // A large read makes the kernel attempt large dump skbs > - ASSERT_EQ(lo_set_up(inet_sock, true), 0); > + ASSERT_EQ(if_set_up(inet_sock, "lo", true), 0); > n = recv(netlink_sock, buf, sizeof(buf), 0); > ASSERT_GE(n, (ssize_t)sizeof(struct nlmsghdr)); > > // Leave one notification queued, then start the dump > - ASSERT_EQ(lo_set_up(inet_sock, false), 0); > + ASSERT_EQ(if_set_up(inet_sock, "lo", false), 0); > n = send(netlink_sock, &dump_links, sizeof(dump_links), 0); > ASSERT_EQ(n, sizeof(dump_links)); > > @@ -362,4 +362,267 @@ TEST(dump_with_queued_ntf) > close(inet_sock); > } > > +#define BIG_RT_TABLE 100 > +#define BIG_RT_IFINDEX 100 > +#define BIG_RT4_NH 1500 > +#define BIG_RT6_NH 500 > + > +static const struct { > + struct nlmsghdr nlhdr; > + struct ifinfomsg ifm; > + struct nlattr name_hdr; > + char name[8]; > + struct nlattr linkinfo_hdr; > + struct nlattr kind_hdr; > + char kind[8]; > +} new_dummy = { > + .nlhdr = { > + .nlmsg_len = sizeof(new_dummy), > + .nlmsg_type = RTM_NEWLINK, > + .nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | NLM_F_CREATE | > + NLM_F_EXCL, > + .nlmsg_seq = 1, > + }, > + .ifm = { > + .ifi_family = AF_UNSPEC, > + .ifi_index = BIG_RT_IFINDEX, > + }, > + .name_hdr = { > + .nla_len = 4 + sizeof("dummy0"), > + .nla_type = IFLA_IFNAME, > + }, > + .name = "dummy0", > + .linkinfo_hdr = { > + .nla_len = 4 + 4 + 8, > + .nla_type = IFLA_LINKINFO, > + }, > + .kind_hdr = { > + .nla_len = 4 + sizeof("dummy"), > + .nla_type = IFLA_INFO_KIND, > + }, > + .kind = "dummy", > +}; > + > +static struct { > + struct nlmsghdr nlhdr; > + struct rtmsg rtm; > + struct nlattr dst_hdr; > + __u8 dst[4]; > + struct nlattr table_hdr; > + __u32 table; > + struct nlattr mp_hdr; > + struct rtnexthop nh[BIG_RT4_NH]; > +} new_route4 = { > + .nlhdr = { > + .nlmsg_len = sizeof(new_route4), > + .nlmsg_type = RTM_NEWROUTE, > + .nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | NLM_F_CREATE | > + NLM_F_EXCL, > + .nlmsg_seq = 1, > + }, > + .rtm = { > + .rtm_family = AF_INET, > + .rtm_dst_len = 24, > + .rtm_protocol = RTPROT_STATIC, > + .rtm_scope = RT_SCOPE_LINK, > + .rtm_type = RTN_UNICAST, > + }, > + .dst_hdr = { > + .nla_len = 4 + 4, > + .nla_type = RTA_DST, > + }, > + .dst = { 198, 51, 100, 0 }, > + .table_hdr = { > + .nla_len = 4 + 4, > + .nla_type = RTA_TABLE, > + }, > + .table = BIG_RT_TABLE, > + .mp_hdr = { > + .nla_len = 4 + sizeof(new_route4.nh), > + .nla_type = RTA_MULTIPATH, > + }, > +}; > + > +struct rtnexthop6 { > + struct rtnexthop rtnh; > + struct nlattr gw_hdr; > + __u8 gw[16]; > +}; > + > +static struct { > + struct nlmsghdr nlhdr; > + struct rtmsg rtm; > + struct nlattr dst_hdr; > + __u8 dst[16]; > + struct nlattr table_hdr; > + __u32 table; > + struct nlattr mp_hdr; > + struct rtnexthop6 nh[BIG_RT6_NH]; > +} new_route6 = { > + .nlhdr = { > + .nlmsg_len = sizeof(new_route6), > + .nlmsg_type = RTM_NEWROUTE, > + .nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | NLM_F_CREATE | > + NLM_F_EXCL, > + .nlmsg_seq = 1, > + }, > + .rtm = { > + .rtm_family = AF_INET6, > + .rtm_dst_len = 64, > + .rtm_protocol = RTPROT_STATIC, > + .rtm_scope = RT_SCOPE_UNIVERSE, > + .rtm_type = RTN_UNICAST, > + }, > + .dst_hdr = { > + .nla_len = 4 + 16, > + .nla_type = RTA_DST, > + }, > + .dst = { 0x20, 0x01, 0x0d, 0xb8 }, // 2001:db8::/64 > + .table_hdr = { > + .nla_len = 4 + 4, > + .nla_type = RTA_TABLE, > + }, > + .table = BIG_RT_TABLE, > + .mp_hdr = { > + .nla_len = 4 + sizeof(new_route6.nh), > + .nla_type = RTA_MULTIPATH, > + }, > +}; > + > +static struct { > + struct nlmsghdr nlhdr; > + struct rtmsg rtm; > +} dump_routes = { > + .nlhdr = { > + .nlmsg_len = sizeof(dump_routes), > + .nlmsg_type = RTM_GETROUTE, > + .nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP, > + .nlmsg_seq = 2, > + }, > + .rtm = { > + .rtm_table = BIG_RT_TABLE, > + }, > +}; > + > +static int nl_request_ack(int sock, const void *req, size_t len) > +{ > + struct nlmsghdr *nlh; > + char buf[4096]; > + ssize_t n; > + > + if (send(sock, req, len, 0) != (ssize_t)len) > + return -errno; > + n = recv(sock, buf, sizeof(buf), 0); > + if (n < 0) > + return -errno; > + nlh = (struct nlmsghdr *)buf; > + if (!NLMSG_OK(nlh, n) || nlh->nlmsg_type != NLMSG_ERROR) > + return -EPROTO; > + return *(int *)NLMSG_DATA(nlh); > +} > + > +// Dump table BIG_RT_TABLE on a fresh socket, so the first dump skb is > +// small, and count routes. The table holds only one route, too large for > +// that skb. Returns the status from NLMSG_DONE or NLMSG_ERROR. > +static int dump_big_table(struct __test_metadata *_metadata, int family, > + int *routes) > +{ > + int netlink_sock, i, ret = 1; > + char buf[32768]; > + int one = 1; > + ssize_t n; > + > + netlink_sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE); > + ASSERT_GE(netlink_sock, 0); > + ASSERT_EQ(setsockopt(netlink_sock, SOL_NETLINK, NETLINK_GET_STRICT_CHK, > + &one, sizeof(one)), 0); > + > + dump_routes.rtm.rtm_family = family; > + n = send(netlink_sock, &dump_routes, sizeof(dump_routes), 0); > + ASSERT_EQ(n, sizeof(dump_routes)); > + > + *routes = 0; > + for (i = 0; i < 100 && ret > 0; i++) { > + struct nlmsghdr *nlh; > + > + n = recv(netlink_sock, buf, sizeof(buf), 0); > + ASSERT_GE(n, 0); > + > + for (nlh = (struct nlmsghdr *)buf; NLMSG_OK(nlh, n); > + nlh = NLMSG_NEXT(nlh, n)) { > + if (nlh->nlmsg_type == RTM_NEWROUTE) > + (*routes)++; > + if (nlh->nlmsg_type == NLMSG_DONE || > + nlh->nlmsg_type == NLMSG_ERROR) { > + ret = *(int *)NLMSG_DATA(nlh); > + break; > + } > + } > + } > + EXPECT_LE(ret, 0); > + > + close(netlink_sock); > + return ret; > +} > + > +// A route that doesn't fit in the first dump skb must either be dumped or > +// end the dump with EMSGSIZE. It must not end the dump as if complete. > +TEST(dump_large_route) > +{ > + int netlink_sock, inet_sock, i, ret, routes; > + > + ret = unshare(CLONE_NEWNET); > + if (ret && errno == EPERM) > + SKIP(return, "Needs CAP_SYS_ADMIN for a netns"); > + ASSERT_EQ(ret, 0); > + > + inet_sock = socket(AF_INET, SOCK_DGRAM, 0); > + ASSERT_GE(inet_sock, 0); > + netlink_sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE); > + ASSERT_GE(netlink_sock, 0); > + > + ret = nl_request_ack(netlink_sock, &new_dummy, sizeof(new_dummy)); > + if (ret == -EOPNOTSUPP) > + SKIP(return, "Needs CONFIG_DUMMY"); > + ASSERT_EQ(ret, 0); > + ASSERT_EQ(if_set_up(inet_sock, "lo", true), 0); > + ASSERT_EQ(if_set_up(inet_sock, "dummy0", true), 0); > + > + for (i = 0; i < BIG_RT4_NH; i++) { > + new_route4.nh[i].rtnh_len = sizeof(new_route4.nh[i]); > + new_route4.nh[i].rtnh_ifindex = 1; // lo > + } > + ASSERT_EQ(nl_request_ack(netlink_sock, &new_route4, > + sizeof(new_route4)), 0); > + > + for (i = 0; i < BIG_RT6_NH; i++) { > + struct rtnexthop6 *nh = &new_route6.nh[i]; > + > + nh->rtnh.rtnh_len = sizeof(*nh); > + nh->rtnh.rtnh_ifindex = BIG_RT_IFINDEX; > + nh->gw_hdr.nla_len = sizeof(nh->gw_hdr) + sizeof(nh->gw); > + nh->gw_hdr.nla_type = RTA_GATEWAY; > + nh->gw[0] = 0xfe; // fe80:: > + nh->gw[1] = 0x80; > + nh->gw[14] = (i + 1) >> 8; > + nh->gw[15] = (i + 1) & 0xff; > + } > + ASSERT_EQ(nl_request_ack(netlink_sock, &new_route6, > + sizeof(new_route6)), 0); > + > + // The ACK reads above used large buffers, which raise the dump > + // skb size for this socket. Dump on fresh sockets instead. > + close(netlink_sock); > + > + ret = dump_big_table(_metadata, AF_INET, &routes); > + if (ret != -EMSGSIZE) > + EXPECT_EQ(routes, 1); > + > + ret = dump_big_table(_metadata, AF_INET6, &routes); > + if (ret != -EMSGSIZE) > + EXPECT_EQ(routes, 1); > + > + close(inet_sock); > +} > + > TEST_HARNESS_MAIN > -- > 2.53.0 > Tested-by: Hangbin Liu Reviewed-by: Hangbin Liu