From 756cce3d00d37aa0dfb7e1ba8b1aca6627068551 Mon Sep 17 00:00:00 2001 From: Cezar Bulinaru Date: Wed, 3 Aug 2022 02:28:16 -0400 Subject: [PATCH] selftests: add few test cases for tap driver Few test cases related to the fix for 87b674ac3159: "net: check if protocol extracted by virtio_net_hdr_set_proto is correct" Need test for the case when a non-standard packet (GSO without NEEDS_CSUM) sent to the tap device causes a BUG check in the tap driver. Signed-off-by: Cezar Bulinaru Reviewed-by: Willem de Bruijn Signed-off-by: David S. Miller --- tools/testing/selftests/net/.gitignore | 3 +- tools/testing/selftests/net/Makefile | 2 +- tools/testing/selftests/net/tap.c | 434 +++++++++++++++++++++++++ 3 files changed, 437 insertions(+), 2 deletions(-) create mode 100644 tools/testing/selftests/net/tap.c diff --git a/tools/testing/selftests/net/.gitignore b/tools/testing/selftests/net/.gitignore index 892306bdb47db..0e5751af6247f 100644 --- a/tools/testing/selftests/net/.gitignore +++ b/tools/testing/selftests/net/.gitignore @@ -38,4 +38,5 @@ ioam6_parser toeplitz tun cmsg_sender -unix_connect \ No newline at end of file +unix_connect +tap \ No newline at end of file diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile index e2dfef8b78a76..c0ee2955fe542 100644 --- a/tools/testing/selftests/net/Makefile +++ b/tools/testing/selftests/net/Makefile @@ -57,7 +57,7 @@ TEST_GEN_FILES += ipsec TEST_GEN_FILES += ioam6_parser TEST_GEN_FILES += gro TEST_GEN_PROGS = reuseport_bpf reuseport_bpf_cpu reuseport_bpf_numa -TEST_GEN_PROGS += reuseport_dualstack reuseaddr_conflict tls tun +TEST_GEN_PROGS += reuseport_dualstack reuseaddr_conflict tls tun tap TEST_GEN_FILES += toeplitz TEST_GEN_FILES += cmsg_sender TEST_GEN_FILES += stress_reuseport_listen diff --git a/tools/testing/selftests/net/tap.c b/tools/testing/selftests/net/tap.c new file mode 100644 index 0000000000000..247c3b3ac1c97 --- /dev/null +++ b/tools/testing/selftests/net/tap.c @@ -0,0 +1,434 @@ +// SPDX-License-Identifier: GPL-2.0 + +#define _GNU_SOURCE + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "../kselftest_harness.h" + +static const char param_dev_tap_name[] = "xmacvtap0"; +static const char param_dev_dummy_name[] = "xdummy0"; +static unsigned char param_hwaddr_src[] = { 0x00, 0xfe, 0x98, 0x14, 0x22, 0x42 }; +static unsigned char param_hwaddr_dest[] = { + 0x00, 0xfe, 0x98, 0x94, 0xd2, 0x43 +}; + +#define MAX_RTNL_PAYLOAD (2048) +#define PKT_DATA 0xCB +#define TEST_PACKET_SZ (sizeof(struct virtio_net_hdr) + ETH_HLEN + ETH_MAX_MTU) + +static struct rtattr *rtattr_add(struct nlmsghdr *nh, unsigned short type, + unsigned short len) +{ + struct rtattr *rta = + (struct rtattr *)((uint8_t *)nh + RTA_ALIGN(nh->nlmsg_len)); + rta->rta_type = type; + rta->rta_len = RTA_LENGTH(len); + nh->nlmsg_len = RTA_ALIGN(nh->nlmsg_len) + RTA_ALIGN(rta->rta_len); + return rta; +} + +static struct rtattr *rtattr_begin(struct nlmsghdr *nh, unsigned short type) +{ + return rtattr_add(nh, type, 0); +} + +static void rtattr_end(struct nlmsghdr *nh, struct rtattr *attr) +{ + uint8_t *end = (uint8_t *)nh + nh->nlmsg_len; + + attr->rta_len = end - (uint8_t *)attr; +} + +static struct rtattr *rtattr_add_str(struct nlmsghdr *nh, unsigned short type, + const char *s) +{ + struct rtattr *rta = rtattr_add(nh, type, strlen(s)); + + memcpy(RTA_DATA(rta), s, strlen(s)); + return rta; +} + +static struct rtattr *rtattr_add_strsz(struct nlmsghdr *nh, unsigned short type, + const char *s) +{ + struct rtattr *rta = rtattr_add(nh, type, strlen(s) + 1); + + strcpy(RTA_DATA(rta), s); + return rta; +} + +static struct rtattr *rtattr_add_any(struct nlmsghdr *nh, unsigned short type, + const void *arr, size_t len) +{ + struct rtattr *rta = rtattr_add(nh, type, len); + + memcpy(RTA_DATA(rta), arr, len); + return rta; +} + +static int dev_create(const char *dev, const char *link_type, + int (*fill_rtattr)(struct nlmsghdr *nh), + int (*fill_info_data)(struct nlmsghdr *nh)) +{ + struct { + struct nlmsghdr nh; + struct ifinfomsg info; + unsigned char data[MAX_RTNL_PAYLOAD]; + } req; + struct rtattr *link_info, *info_data; + int ret, rtnl; + + rtnl = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE); + if (rtnl < 0) { + fprintf(stderr, "%s: socket %s\n", __func__, strerror(errno)); + return 1; + } + + memset(&req, 0, sizeof(req)); + req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(req.info)); + req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE; + req.nh.nlmsg_type = RTM_NEWLINK; + + req.info.ifi_family = AF_UNSPEC; + req.info.ifi_type = 1; + req.info.ifi_index = 0; + req.info.ifi_flags = IFF_BROADCAST | IFF_UP; + req.info.ifi_change = 0xffffffff; + + rtattr_add_str(&req.nh, IFLA_IFNAME, dev); + + if (fill_rtattr) { + ret = fill_rtattr(&req.nh); + if (ret) + return ret; + } + + link_info = rtattr_begin(&req.nh, IFLA_LINKINFO); + + rtattr_add_strsz(&req.nh, IFLA_INFO_KIND, link_type); + + if (fill_info_data) { + info_data = rtattr_begin(&req.nh, IFLA_INFO_DATA); + ret = fill_info_data(&req.nh); + if (ret) + return ret; + rtattr_end(&req.nh, info_data); + } + + rtattr_end(&req.nh, link_info); + + ret = send(rtnl, &req, req.nh.nlmsg_len, 0); + if (ret < 0) + fprintf(stderr, "%s: send %s\n", __func__, strerror(errno)); + ret = (unsigned int)ret != req.nh.nlmsg_len; + + close(rtnl); + return ret; +} + +static int dev_delete(const char *dev) +{ + struct { + struct nlmsghdr nh; + struct ifinfomsg info; + unsigned char data[MAX_RTNL_PAYLOAD]; + } req; + int ret, rtnl; + + rtnl = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE); + if (rtnl < 0) { + fprintf(stderr, "%s: socket %s\n", __func__, strerror(errno)); + return 1; + } + + memset(&req, 0, sizeof(req)); + req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(req.info)); + req.nh.nlmsg_flags = NLM_F_REQUEST; + req.nh.nlmsg_type = RTM_DELLINK; + + req.info.ifi_family = AF_UNSPEC; + + rtattr_add_str(&req.nh, IFLA_IFNAME, dev); + + ret = send(rtnl, &req, req.nh.nlmsg_len, 0); + if (ret < 0) + fprintf(stderr, "%s: send %s\n", __func__, strerror(errno)); + + ret = (unsigned int)ret != req.nh.nlmsg_len; + + close(rtnl); + return ret; +} + +static int macvtap_fill_rtattr(struct nlmsghdr *nh) +{ + int ifindex; + + ifindex = if_nametoindex(param_dev_dummy_name); + if (ifindex == 0) { + fprintf(stderr, "%s: ifindex %s\n", __func__, strerror(errno)); + return -errno; + } + + rtattr_add_any(nh, IFLA_LINK, &ifindex, sizeof(ifindex)); + rtattr_add_any(nh, IFLA_ADDRESS, param_hwaddr_src, ETH_ALEN); + + return 0; +} + +static int opentap(const char *devname) +{ + int ifindex; + char buf[256]; + int fd; + struct ifreq ifr; + + ifindex = if_nametoindex(devname); + if (ifindex == 0) { + fprintf(stderr, "%s: ifindex %s\n", __func__, strerror(errno)); + return -errno; + } + + sprintf(buf, "/dev/tap%d", ifindex); + fd = open(buf, O_RDWR | O_NONBLOCK); + if (fd < 0) { + fprintf(stderr, "%s: open %s\n", __func__, strerror(errno)); + return -errno; + } + + memset(&ifr, 0, sizeof(ifr)); + strcpy(ifr.ifr_name, devname); + ifr.ifr_flags = IFF_TAP | IFF_NO_PI | IFF_VNET_HDR | IFF_MULTI_QUEUE; + if (ioctl(fd, TUNSETIFF, &ifr, sizeof(ifr)) < 0) + return -errno; + return fd; +} + +size_t build_eth(uint8_t *buf, uint16_t proto) +{ + struct ethhdr *eth = (struct ethhdr *)buf; + + eth->h_proto = htons(proto); + memcpy(eth->h_source, param_hwaddr_src, ETH_ALEN); + memcpy(eth->h_dest, param_hwaddr_dest, ETH_ALEN); + + return ETH_HLEN; +} + +static uint32_t add_csum(const uint8_t *buf, int len) +{ + uint32_t sum = 0; + uint16_t *sbuf = (uint16_t *)buf; + + while (len > 1) { + sum += *sbuf++; + len -= 2; + } + + if (len) + sum += *(uint8_t *)sbuf; + + return sum; +} + +static uint16_t finish_ip_csum(uint32_t sum) +{ + uint16_t lo = sum & 0xffff; + uint16_t hi = sum >> 16; + + return ~(lo + hi); + +} + +static uint16_t build_ip_csum(const uint8_t *buf, int len, + uint32_t sum) +{ + sum += add_csum(buf, len); + return finish_ip_csum(sum); +} + +static int build_ipv4_header(uint8_t *buf, int payload_len) +{ + struct iphdr *iph = (struct iphdr *)buf; + + iph->ihl = 5; + iph->version = 4; + iph->ttl = 8; + iph->tot_len = + htons(sizeof(*iph) + sizeof(struct udphdr) + payload_len); + iph->id = htons(1337); + iph->protocol = IPPROTO_UDP; + iph->saddr = htonl((172 << 24) | (17 << 16) | 2); + iph->daddr = htonl((172 << 24) | (17 << 16) | 1); + iph->check = build_ip_csum(buf, iph->ihl << 2, 0); + + return iph->ihl << 2; +} + +static int build_udp_packet(uint8_t *buf, int payload_len, bool csum_off) +{ + const int ip4alen = sizeof(uint32_t); + struct udphdr *udph = (struct udphdr *)buf; + int len = sizeof(*udph) + payload_len; + uint32_t sum = 0; + + udph->source = htons(22); + udph->dest = htons(58822); + udph->len = htons(len); + + memset(buf + sizeof(struct udphdr), PKT_DATA, payload_len); + + sum = add_csum(buf - 2 * ip4alen, 2 * ip4alen); + sum += htons(IPPROTO_UDP) + udph->len; + + if (!csum_off) + sum += add_csum(buf, len); + + udph->check = finish_ip_csum(sum); + + return sizeof(*udph) + payload_len; +} + +size_t build_test_packet_valid_udp_gso(uint8_t *buf, size_t payload_len) +{ + uint8_t *cur = buf; + struct virtio_net_hdr *vh = (struct virtio_net_hdr *)buf; + + vh->hdr_len = ETH_HLEN + sizeof(struct iphdr) + sizeof(struct udphdr); + vh->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; + vh->csum_start = ETH_HLEN + sizeof(struct iphdr); + vh->csum_offset = __builtin_offsetof(struct udphdr, check); + vh->gso_type = VIRTIO_NET_HDR_GSO_UDP; + vh->gso_size = ETH_DATA_LEN - sizeof(struct iphdr); + cur += sizeof(*vh); + + cur += build_eth(cur, ETH_P_IP); + cur += build_ipv4_header(cur, payload_len); + cur += build_udp_packet(cur, payload_len, true); + + return cur - buf; +} + +size_t build_test_packet_valid_udp_csum(uint8_t *buf, size_t payload_len) +{ + uint8_t *cur = buf; + struct virtio_net_hdr *vh = (struct virtio_net_hdr *)buf; + + vh->flags = VIRTIO_NET_HDR_F_DATA_VALID; + vh->gso_type = VIRTIO_NET_HDR_GSO_NONE; + cur += sizeof(*vh); + + cur += build_eth(cur, ETH_P_IP); + cur += build_ipv4_header(cur, payload_len); + cur += build_udp_packet(cur, payload_len, false); + + return cur - buf; +} + +size_t build_test_packet_crash_tap_invalid_eth_proto(uint8_t *buf, + size_t payload_len) +{ + uint8_t *cur = buf; + struct virtio_net_hdr *vh = (struct virtio_net_hdr *)buf; + + vh->hdr_len = ETH_HLEN + sizeof(struct iphdr) + sizeof(struct udphdr); + vh->flags = 0; + vh->gso_type = VIRTIO_NET_HDR_GSO_UDP; + vh->gso_size = ETH_DATA_LEN - sizeof(struct iphdr); + cur += sizeof(*vh); + + cur += build_eth(cur, 0); + cur += sizeof(struct iphdr) + sizeof(struct udphdr); + cur += build_ipv4_header(cur, payload_len); + cur += build_udp_packet(cur, payload_len, true); + cur += payload_len; + + return cur - buf; +} + +FIXTURE(tap) +{ + int fd; +}; + +FIXTURE_SETUP(tap) +{ + int ret; + + ret = dev_create(param_dev_dummy_name, "dummy", NULL, NULL); + EXPECT_EQ(ret, 0); + + ret = dev_create(param_dev_tap_name, "macvtap", macvtap_fill_rtattr, + NULL); + EXPECT_EQ(ret, 0); + + self->fd = opentap(param_dev_tap_name); + ASSERT_GE(self->fd, 0); +} + +FIXTURE_TEARDOWN(tap) +{ + int ret; + + if (self->fd != -1) + close(self->fd); + + ret = dev_delete(param_dev_tap_name); + EXPECT_EQ(ret, 0); + + ret = dev_delete(param_dev_dummy_name); + EXPECT_EQ(ret, 0); +} + +TEST_F(tap, test_packet_valid_udp_gso) +{ + uint8_t pkt[TEST_PACKET_SZ]; + size_t off; + int ret; + + memset(pkt, 0, sizeof(pkt)); + off = build_test_packet_valid_udp_gso(pkt, 1021); + ret = write(self->fd, pkt, off); + ASSERT_EQ(ret, off); +} + +TEST_F(tap, test_packet_valid_udp_csum) +{ + uint8_t pkt[TEST_PACKET_SZ]; + size_t off; + int ret; + + memset(pkt, 0, sizeof(pkt)); + off = build_test_packet_valid_udp_csum(pkt, 1024); + ret = write(self->fd, pkt, off); + ASSERT_EQ(ret, off); +} + +TEST_F(tap, test_packet_crash_tap_invalid_eth_proto) +{ + uint8_t pkt[TEST_PACKET_SZ]; + size_t off; + int ret; + + memset(pkt, 0, sizeof(pkt)); + off = build_test_packet_crash_tap_invalid_eth_proto(pkt, 1024); + ret = write(self->fd, pkt, off); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, EINVAL); +} + +TEST_HARNESS_MAIN -- 2.39.5