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selftests: net: test IPV6_DONTFRAG
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Test setting IPV6_DONTFRAG via setsockopt and cmsg
across socket types.

Output without the kernel support (this series):

    Case DONTFRAG ICMP setsock returned 0, expected 1
    Case DONTFRAG ICMP cmsg returned 0, expected 1
    Case DONTFRAG ICMP both returned 0, expected 1
    Case DONTFRAG ICMP diff returned 0, expected 1
  FAIL - 4/24 cases failed

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Jakub Kicinski authored and David S. Miller committed Feb 17, 2022
1 parent 1365122 commit 6f97c7c
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Showing 2 changed files with 147 additions and 23 deletions.
65 changes: 65 additions & 0 deletions tools/testing/selftests/net/cmsg_ipv6.sh
View file
Original file line number Diff line number Diff line change
@@ -0,0 +1,65 @@
#!/bin/bash
# SPDX-License-Identifier: GPL-2.0

NS=ns
IP6=2001:db8:1::1/64
TGT6=2001:db8:1::2

cleanup()
{
ip netns del $NS
}

trap cleanup EXIT

NSEXE="ip netns exec $NS"

# Namespaces
ip netns add $NS

$NSEXE sysctl -w net.ipv4.ping_group_range='0 2147483647' > /dev/null

# Connectivity
ip -netns $NS link add type dummy
ip -netns $NS link set dev dummy0 up
ip -netns $NS addr add $IP6 dev dummy0

# Test
BAD=0
TOTAL=0

check_result() {
((TOTAL++))
if [ $1 -ne $2 ]; then
echo " Case $3 returned $1, expected $2"
((BAD++))
fi
}

# IPV6_DONTFRAG
for ovr in setsock cmsg both diff; do
for df in 0 1; do
for p in u i r; do
[ $p == "u" ] && prot=UDP
[ $p == "i" ] && prot=ICMP
[ $p == "r" ] && prot=RAW

[ $ovr == "setsock" ] && m="-F $df"
[ $ovr == "cmsg" ] && m="-f $df"
[ $ovr == "both" ] && m="-F $df -f $df"
[ $ovr == "diff" ] && m="-F $((1 - df)) -f $df"

$NSEXE ./cmsg_sender -s -S 2000 -6 -p $p $m $TGT6 1234
check_result $? $df "DONTFRAG $prot $ovr"
done
done
done

# Summary
if [ $BAD -ne 0 ]; then
echo "FAIL - $BAD/$TOTAL cases failed"
exit 1
else
echo "OK"
exit 0
fi
105 changes: 82 additions & 23 deletions tools/testing/selftests/net/cmsg_sender.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -33,30 +33,38 @@ enum {
ERN_CMSG_RCV,
};

struct option_cmsg_u32 {
bool ena;
unsigned int val;
};

struct options {
bool silent_send;
const char *host;
const char *service;
unsigned int size;
struct {
unsigned int mark;
unsigned int dontfrag;
} sockopt;
struct {
unsigned int family;
unsigned int type;
unsigned int proto;
} sock;
struct {
bool ena;
unsigned int val;
} mark;
struct option_cmsg_u32 mark;
struct {
bool ena;
unsigned int delay;
} txtime;
struct {
bool ena;
} ts;
struct {
struct option_cmsg_u32 dontfrag;
} v6;
} opt = {
.size = 13,
.sock = {
.family = AF_UNSPEC,
.type = SOCK_DGRAM,
Expand All @@ -72,6 +80,7 @@ static void __attribute__((noreturn)) cs_usage(const char *bin)
printf("Usage: %s [opts] <dst host> <dst port / service>\n", bin);
printf("Options:\n"
"\t\t-s Silent send() failures\n"
"\t\t-S send() size\n"
"\t\t-4/-6 Force IPv4 / IPv6 only\n"
"\t\t-p prot Socket protocol\n"
"\t\t (u = UDP (default); i = ICMP; r = RAW)\n"
Expand All @@ -80,6 +89,8 @@ static void __attribute__((noreturn)) cs_usage(const char *bin)
"\t\t-M val Set SO_MARK via setsockopt\n"
"\t\t-d val Set SO_TXTIME with given delay (usec)\n"
"\t\t-t Enable time stamp reporting\n"
"\t\t-f val Set don't fragment via cmsg\n"
"\t\t-F val Set don't fragment via setsockopt\n"
"");
exit(ERN_HELP);
}
Expand All @@ -88,11 +99,14 @@ static void cs_parse_args(int argc, char *argv[])
{
char o;

while ((o = getopt(argc, argv, "46sp:m:M:d:t")) != -1) {
while ((o = getopt(argc, argv, "46sS:p:m:M:d:tf:F:")) != -1) {
switch (o) {
case 's':
opt.silent_send = true;
break;
case 'S':
opt.size = atoi(optarg);
break;
case '4':
opt.sock.family = AF_INET;
break;
Expand Down Expand Up @@ -126,6 +140,13 @@ static void cs_parse_args(int argc, char *argv[])
case 't':
opt.ts.ena = true;
break;
case 'f':
opt.v6.dontfrag.ena = true;
opt.v6.dontfrag.val = atoi(optarg);
break;
case 'F':
opt.sockopt.dontfrag = atoi(optarg);
break;
}
}

Expand All @@ -136,6 +157,38 @@ static void cs_parse_args(int argc, char *argv[])
opt.service = argv[optind + 1];
}

static void memrnd(void *s, size_t n)
{
int *dword = s;
char *byte;

for (; n >= 4; n -= 4)
*dword++ = rand();
byte = (void *)dword;
while (n--)
*byte++ = rand();
}

static void
ca_write_cmsg_u32(char *cbuf, size_t cbuf_sz, size_t *cmsg_len,
int level, int optname, struct option_cmsg_u32 *uopt)
{
struct cmsghdr *cmsg;

if (!uopt->ena)
return;

cmsg = (struct cmsghdr *)(cbuf + *cmsg_len);
*cmsg_len += CMSG_SPACE(sizeof(__u32));
if (cbuf_sz < *cmsg_len)
error(ERN_CMSG_WR, EFAULT, "cmsg buffer too small");

cmsg->cmsg_level = level;
cmsg->cmsg_type = optname;
cmsg->cmsg_len = CMSG_LEN(sizeof(__u32));
*(__u32 *)CMSG_DATA(cmsg) = uopt->val;
}

static void
cs_write_cmsg(int fd, struct msghdr *msg, char *cbuf, size_t cbuf_sz)
{
Expand All @@ -145,17 +198,11 @@ cs_write_cmsg(int fd, struct msghdr *msg, char *cbuf, size_t cbuf_sz)
msg->msg_control = cbuf;
cmsg_len = 0;

if (opt.mark.ena) {
cmsg = (struct cmsghdr *)(cbuf + cmsg_len);
cmsg_len += CMSG_SPACE(sizeof(__u32));
if (cbuf_sz < cmsg_len)
error(ERN_CMSG_WR, EFAULT, "cmsg buffer too small");
ca_write_cmsg_u32(cbuf, cbuf_sz, &cmsg_len,
SOL_SOCKET, SO_MARK, &opt.mark);
ca_write_cmsg_u32(cbuf, cbuf_sz, &cmsg_len,
SOL_IPV6, IPV6_DONTFRAG, &opt.v6.dontfrag);

cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SO_MARK;
cmsg->cmsg_len = CMSG_LEN(sizeof(__u32));
*(__u32 *)CMSG_DATA(cmsg) = opt.mark.val;
}
if (opt.txtime.ena) {
struct sock_txtime so_txtime = {
.clockid = CLOCK_MONOTONIC,
Expand Down Expand Up @@ -286,18 +333,33 @@ cs_read_cmsg(int fd, struct msghdr *msg, char *cbuf, size_t cbuf_sz)
}
}

static void ca_set_sockopts(int fd)
{
if (opt.sockopt.mark &&
setsockopt(fd, SOL_SOCKET, SO_MARK,
&opt.sockopt.mark, sizeof(opt.sockopt.mark)))
error(ERN_SOCKOPT, errno, "setsockopt SO_MARK");
if (opt.sockopt.dontfrag &&
setsockopt(fd, SOL_IPV6, IPV6_DONTFRAG,
&opt.sockopt.dontfrag, sizeof(opt.sockopt.dontfrag)))
error(ERN_SOCKOPT, errno, "setsockopt IPV6_DONTFRAG");
}

int main(int argc, char *argv[])
{
char buf[] = "blablablabla";
struct addrinfo hints, *ai;
struct iovec iov[1];
struct msghdr msg;
char cbuf[1024];
char *buf;
int err;
int fd;

cs_parse_args(argc, argv);

buf = malloc(opt.size);
memrnd(buf, opt.size);

memset(&hints, 0, sizeof(hints));
hints.ai_family = opt.sock.family;

Expand Down Expand Up @@ -326,25 +388,22 @@ int main(int argc, char *argv[])
buf[0] = ICMPV6_ECHO_REQUEST;
buf[1] = 0;
} else if (opt.sock.type == SOCK_RAW) {
struct udphdr hdr = { 1, 2, htons(sizeof(buf)), 0 };
struct udphdr hdr = { 1, 2, htons(opt.size), 0 };
struct sockaddr_in6 *sin6 = (void *)ai->ai_addr;;

memcpy(buf, &hdr, sizeof(hdr));
sin6->sin6_port = htons(opt.sock.proto);
}

if (opt.sockopt.mark &&
setsockopt(fd, SOL_SOCKET, SO_MARK,
&opt.sockopt.mark, sizeof(opt.sockopt.mark)))
error(ERN_SOCKOPT, errno, "setsockopt SO_MARK");
ca_set_sockopts(fd);

if (clock_gettime(CLOCK_REALTIME, &time_start_real))
error(ERN_GETTIME, errno, "gettime REALTIME");
if (clock_gettime(CLOCK_MONOTONIC, &time_start_mono))
error(ERN_GETTIME, errno, "gettime MONOTONIC");

iov[0].iov_base = buf;
iov[0].iov_len = sizeof(buf);
iov[0].iov_len = opt.size;

memset(&msg, 0, sizeof(msg));
msg.msg_name = ai->ai_addr;
Expand All @@ -360,7 +419,7 @@ int main(int argc, char *argv[])
fprintf(stderr, "send failed: %s\n", strerror(errno));
err = ERN_SEND;
goto err_out;
} else if (err != sizeof(buf)) {
} else if (err != (int)opt.size) {
fprintf(stderr, "short send\n");
err = ERN_SEND_SHORT;
goto err_out;
Expand Down

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