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selftests: udpgso: Pull up network setup into shell script
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udpgso regression test configures routing and device MTU directly through
uAPI (Netlink, ioctl) to do its job. While there is nothing wrong with it,
it takes more effort than doing it from shell.

Looking forward, we would like to extend the udpgso regression tests to
cover the EIO corner case [1], once it gets addressed. That will require a
dummy device and device feature manipulation to set it up. Which means more
Netlink code.

So, in preparation, pull out network configuration into the shell script
part of the test, so it is easily extendable in the future.

Also, because it now easy to setup routing, add a second local IPv6
address. Because the second address is not managed by the kernel, we can
"replace" the corresponding local route with a reduced-MTU one. This
unblocks the disabled "ipv6 connected" test case. Add a similar setup for
IPv4 for symmetry.

[1] https://lore.kernel.org/netdev/87jzqsld6q.fsf@cloudflare.com/

Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/r/20240207-jakub-krn-635-v3-1-3dfa3da8a7d3@cloudflare.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Jakub Sitnicki authored and Jakub Kicinski committed Feb 9, 2024
1 parent 32b8033 commit d45f5fa
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Showing 2 changed files with 47 additions and 136 deletions.
134 changes: 8 additions & 126 deletions tools/testing/selftests/net/udpgso.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -56,7 +56,6 @@ static bool cfg_do_msgmore;
static bool cfg_do_setsockopt;
static int cfg_specific_test_id = -1;

static const char cfg_ifname[] = "lo";
static unsigned short cfg_port = 9000;

static char buf[ETH_MAX_MTU];
Expand All @@ -69,8 +68,13 @@ struct testcase {
int r_len_last; /* recv(): size of last non-mss dgram, if any */
};

const struct in6_addr addr6 = IN6ADDR_LOOPBACK_INIT;
const struct in_addr addr4 = { .s_addr = __constant_htonl(INADDR_LOOPBACK + 2) };
const struct in6_addr addr6 = {
{ { 0xfd, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 } }, /* fd00::1 */
};

const struct in_addr addr4 = {
__constant_htonl(0x0a000001), /* 10.0.0.1 */
};

struct testcase testcases_v4[] = {
{
Expand Down Expand Up @@ -274,48 +278,6 @@ struct testcase testcases_v6[] = {
}
};

static unsigned int get_device_mtu(int fd, const char *ifname)
{
struct ifreq ifr;

memset(&ifr, 0, sizeof(ifr));

strcpy(ifr.ifr_name, ifname);

if (ioctl(fd, SIOCGIFMTU, &ifr))
error(1, errno, "ioctl get mtu");

return ifr.ifr_mtu;
}

static void __set_device_mtu(int fd, const char *ifname, unsigned int mtu)
{
struct ifreq ifr;

memset(&ifr, 0, sizeof(ifr));

ifr.ifr_mtu = mtu;
strcpy(ifr.ifr_name, ifname);

if (ioctl(fd, SIOCSIFMTU, &ifr))
error(1, errno, "ioctl set mtu");
}

static void set_device_mtu(int fd, int mtu)
{
int val;

val = get_device_mtu(fd, cfg_ifname);
fprintf(stderr, "device mtu (orig): %u\n", val);

__set_device_mtu(fd, cfg_ifname, mtu);
val = get_device_mtu(fd, cfg_ifname);
if (val != mtu)
error(1, 0, "unable to set device mtu to %u\n", val);

fprintf(stderr, "device mtu (test): %u\n", val);
}

static void set_pmtu_discover(int fd, bool is_ipv4)
{
int level, name, val;
Expand Down Expand Up @@ -354,81 +316,6 @@ static unsigned int get_path_mtu(int fd, bool is_ipv4)
return mtu;
}

/* very wordy version of system("ip route add dev lo mtu 1500 127.0.0.3/32") */
static void set_route_mtu(int mtu, bool is_ipv4)
{
struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK };
struct nlmsghdr *nh;
struct rtattr *rta;
struct rtmsg *rt;
char data[NLMSG_ALIGN(sizeof(*nh)) +
NLMSG_ALIGN(sizeof(*rt)) +
NLMSG_ALIGN(RTA_LENGTH(sizeof(addr6))) +
NLMSG_ALIGN(RTA_LENGTH(sizeof(int))) +
NLMSG_ALIGN(RTA_LENGTH(0) + RTA_LENGTH(sizeof(int)))];
int fd, ret, alen, off = 0;

alen = is_ipv4 ? sizeof(addr4) : sizeof(addr6);

fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (fd == -1)
error(1, errno, "socket netlink");

memset(data, 0, sizeof(data));

nh = (void *)data;
nh->nlmsg_type = RTM_NEWROUTE;
nh->nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE;
off += NLMSG_ALIGN(sizeof(*nh));

rt = (void *)(data + off);
rt->rtm_family = is_ipv4 ? AF_INET : AF_INET6;
rt->rtm_table = RT_TABLE_MAIN;
rt->rtm_dst_len = alen << 3;
rt->rtm_protocol = RTPROT_BOOT;
rt->rtm_scope = RT_SCOPE_UNIVERSE;
rt->rtm_type = RTN_UNICAST;
off += NLMSG_ALIGN(sizeof(*rt));

rta = (void *)(data + off);
rta->rta_type = RTA_DST;
rta->rta_len = RTA_LENGTH(alen);
if (is_ipv4)
memcpy(RTA_DATA(rta), &addr4, alen);
else
memcpy(RTA_DATA(rta), &addr6, alen);
off += NLMSG_ALIGN(rta->rta_len);

rta = (void *)(data + off);
rta->rta_type = RTA_OIF;
rta->rta_len = RTA_LENGTH(sizeof(int));
*((int *)(RTA_DATA(rta))) = 1; //if_nametoindex("lo");
off += NLMSG_ALIGN(rta->rta_len);

/* MTU is a subtype in a metrics type */
rta = (void *)(data + off);
rta->rta_type = RTA_METRICS;
rta->rta_len = RTA_LENGTH(0) + RTA_LENGTH(sizeof(int));
off += NLMSG_ALIGN(rta->rta_len);

/* now fill MTU subtype. Note that it fits within above rta_len */
rta = (void *)(((char *) rta) + RTA_LENGTH(0));
rta->rta_type = RTAX_MTU;
rta->rta_len = RTA_LENGTH(sizeof(int));
*((int *)(RTA_DATA(rta))) = mtu;

nh->nlmsg_len = off;

ret = sendto(fd, data, off, 0, (void *)&nladdr, sizeof(nladdr));
if (ret != off)
error(1, errno, "send netlink: %uB != %uB\n", ret, off);

if (close(fd))
error(1, errno, "close netlink");

fprintf(stderr, "route mtu (test): %u\n", mtu);
}

static bool __send_one(int fd, struct msghdr *msg, int flags)
{
int ret;
Expand Down Expand Up @@ -591,15 +478,10 @@ static void run_test(struct sockaddr *addr, socklen_t alen)
/* Do not fragment these datagrams: only succeed if GSO works */
set_pmtu_discover(fdt, addr->sa_family == AF_INET);

if (cfg_do_connectionless) {
set_device_mtu(fdt, CONST_MTU_TEST);
if (cfg_do_connectionless)
run_all(fdt, fdr, addr, alen);
}

if (cfg_do_connected) {
set_device_mtu(fdt, CONST_MTU_TEST + 100);
set_route_mtu(CONST_MTU_TEST, addr->sa_family == AF_INET);

if (connect(fdt, addr, alen))
error(1, errno, "connect");

Expand Down
49 changes: 39 additions & 10 deletions tools/testing/selftests/net/udpgso.sh
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3,27 +3,56 @@
#
# Run a series of udpgso regression tests

set -o errexit
set -o nounset

setup_loopback() {
ip addr add dev lo 10.0.0.1/32
ip addr add dev lo fd00::1/128 nodad noprefixroute
}

test_dev_mtu() {
setup_loopback
# Reduce loopback MTU
ip link set dev lo mtu 1500
}

test_route_mtu() {
setup_loopback
# Remove default local routes
ip route del local 10.0.0.1/32 table local dev lo
ip route del local fd00::1/128 table local dev lo
# Install local routes with reduced MTU
ip route add local 10.0.0.1/32 table local dev lo mtu 1500
ip route add local fd00::1/128 table local dev lo mtu 1500
}

if [ "$#" -gt 0 ]; then
"$1"
shift 2 # pop "test_*" arg and "--" delimiter
exec "$@"
fi

echo "ipv4 cmsg"
./in_netns.sh ./udpgso -4 -C
./in_netns.sh "$0" test_dev_mtu -- ./udpgso -4 -C

echo "ipv4 setsockopt"
./in_netns.sh ./udpgso -4 -C -s
./in_netns.sh "$0" test_dev_mtu -- ./udpgso -4 -C -s

echo "ipv6 cmsg"
./in_netns.sh ./udpgso -6 -C
./in_netns.sh "$0" test_dev_mtu -- ./udpgso -6 -C

echo "ipv6 setsockopt"
./in_netns.sh ./udpgso -6 -C -s
./in_netns.sh "$0" test_dev_mtu -- ./udpgso -6 -C -s

echo "ipv4 connected"
./in_netns.sh ./udpgso -4 -c
./in_netns.sh "$0" test_route_mtu -- ./udpgso -4 -c

# blocked on 2nd loopback address
# echo "ipv6 connected"
# ./in_netns.sh ./udpgso -6 -c
echo "ipv6 connected"
./in_netns.sh "$0" test_route_mtu -- ./udpgso -6 -c

echo "ipv4 msg_more"
./in_netns.sh ./udpgso -4 -C -m
./in_netns.sh "$0" test_dev_mtu -- ./udpgso -4 -C -m

echo "ipv6 msg_more"
./in_netns.sh ./udpgso -6 -C -m
./in_netns.sh "$0" test_dev_mtu -- ./udpgso -6 -C -m

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