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Message-Id: <20190122180253.128336-5-posk@google.com>
Date: Tue, 22 Jan 2019 10:02:53 -0800
From: Peter Oskolkov <posk@...gle.com>
To: David Miller <davem@...emloft.net>, netdev@...r.kernel.org
Cc: Peter Oskolkov <posk.devel@...il.com>,
Peter Oskolkov <posk@...gle.com>
Subject: [PATCH net-next 4/4] selftests: net: ip_defrag: cover new IPv6
defrag behavior
This patch adds several changes to the ip_defrag selftest, to cover
new IPv6 defrag behavior:
- min IPv6 frag size is now 8 instead of 1280
- new test cases to cover IPv6 defragmentation in nf_conntrack_reasm.c
- new "permissive" mode in negative (overlap) tests: netfilter
sometimes drops invalid packets without passing them to IPv6
underneath, and thus defragmentation sometimes succeeds when
it is expected to fail; so the permissive mode does not fail the
test if the correct reassembled datagram is received instead of a
timeout.
Signed-off-by: Peter Oskolkov <posk@...gle.com>
---
tools/testing/selftests/net/ip_defrag.c | 69 ++++++++++++------------
tools/testing/selftests/net/ip_defrag.sh | 16 ++++++
2 files changed, 51 insertions(+), 34 deletions(-)
diff --git a/tools/testing/selftests/net/ip_defrag.c b/tools/testing/selftests/net/ip_defrag.c
index 5d56cc0838f6..c0c9ecb891e1 100644
--- a/tools/testing/selftests/net/ip_defrag.c
+++ b/tools/testing/selftests/net/ip_defrag.c
@@ -20,6 +20,7 @@ static bool cfg_do_ipv4;
static bool cfg_do_ipv6;
static bool cfg_verbose;
static bool cfg_overlap;
+static bool cfg_permissive;
static unsigned short cfg_port = 9000;
const struct in_addr addr4 = { .s_addr = __constant_htonl(INADDR_LOOPBACK + 2) };
@@ -35,7 +36,7 @@ const struct in6_addr addr6 = IN6ADDR_LOOPBACK_INIT;
static int payload_len;
static int max_frag_len;
-#define MSG_LEN_MAX 60000 /* Max UDP payload length. */
+#define MSG_LEN_MAX 10000 /* Max UDP payload length. */
#define IP4_MF (1u << 13) /* IPv4 MF flag. */
#define IP6_MF (1) /* IPv6 MF flag. */
@@ -59,13 +60,14 @@ static void recv_validate_udp(int fd_udp)
msg_counter++;
if (cfg_overlap) {
- if (ret != -1)
- error(1, 0, "recv: expected timeout; got %d",
- (int)ret);
- if (errno != ETIMEDOUT && errno != EAGAIN)
- error(1, errno, "recv: expected timeout: %d",
- errno);
- return; /* OK */
+ if (ret == -1 && (errno == ETIMEDOUT || errno == EAGAIN))
+ return; /* OK */
+ if (!cfg_permissive) {
+ if (ret != -1)
+ error(1, 0, "recv: expected timeout; got %d",
+ (int)ret);
+ error(1, errno, "recv: expected timeout: %d", errno);
+ }
}
if (ret == -1)
@@ -203,7 +205,6 @@ static void send_udp_frags(int fd_raw, struct sockaddr *addr,
{
struct ip *iphdr = (struct ip *)ip_frame;
struct ip6_hdr *ip6hdr = (struct ip6_hdr *)ip_frame;
- const bool ipv4 = !ipv6;
int res;
int offset;
int frag_len;
@@ -251,7 +252,7 @@ static void send_udp_frags(int fd_raw, struct sockaddr *addr,
}
/* Occasionally test IPv4 "runs" (see net/ipv4/ip_fragment.c) */
- if (ipv4 && !cfg_overlap && (rand() % 100 < 20) &&
+ if (!cfg_overlap && (rand() % 100 < 20) &&
(payload_len > 9 * max_frag_len)) {
offset = 6 * max_frag_len;
while (offset < (UDP_HLEN + payload_len)) {
@@ -276,41 +277,38 @@ static void send_udp_frags(int fd_raw, struct sockaddr *addr,
while (offset < (UDP_HLEN + payload_len)) {
send_fragment(fd_raw, addr, alen, offset, ipv6);
/* IPv4 ignores duplicates, so randomly send a duplicate. */
- if (ipv4 && (1 == rand() % 100))
+ if (rand() % 100 == 1)
send_fragment(fd_raw, addr, alen, offset, ipv6);
offset += 2 * max_frag_len;
}
if (cfg_overlap) {
- /* Send an extra random fragment. */
+ /* Send an extra random fragment.
+ *
+ * Duplicates and some fragments completely inside
+ * previously sent fragments are dropped/ignored. So
+ * random offset and frag_len can result in a dropped
+ * fragment instead of a dropped queue/packet. Thus we
+ * hard-code offset and frag_len.
+ */
+ if (max_frag_len * 4 < payload_len || max_frag_len < 16) {
+ /* not enough payload for random offset and frag_len. */
+ offset = 8;
+ frag_len = UDP_HLEN + max_frag_len;
+ } else {
+ offset = rand() % (payload_len / 2);
+ frag_len = 2 * max_frag_len + 1 + rand() % 256;
+ }
if (ipv6) {
struct ip6_frag *fraghdr = (struct ip6_frag *)(ip_frame + IP6_HLEN);
/* sendto() returns EINVAL if offset + frag_len is too small. */
- offset = rand() % (UDP_HLEN + payload_len - 1);
- frag_len = max_frag_len + rand() % 256;
/* In IPv6 if !!(frag_len % 8), the fragment is dropped. */
frag_len &= ~0x7;
fraghdr->ip6f_offlg = htons(offset / 8 | IP6_MF);
ip6hdr->ip6_plen = htons(frag_len);
frag_len += IP6_HLEN;
} else {
- /* In IPv4, duplicates and some fragments completely inside
- * previously sent fragments are dropped/ignored. So
- * random offset and frag_len can result in a dropped
- * fragment instead of a dropped queue/packet. So we
- * hard-code offset and frag_len.
- *
- * See ade446403bfb ("net: ipv4: do not handle duplicate
- * fragments as overlapping").
- */
- if (max_frag_len * 4 < payload_len || max_frag_len < 16) {
- /* not enough payload to play with random offset and frag_len. */
- offset = 8;
- frag_len = IP4_HLEN + UDP_HLEN + max_frag_len;
- } else {
- offset = rand() % (payload_len / 2);
- frag_len = 2 * max_frag_len + 1 + rand() % 256;
- }
+ frag_len += IP4_HLEN;
iphdr->ip_off = htons(offset / 8 | IP4_MF);
iphdr->ip_len = htons(frag_len);
}
@@ -327,7 +325,7 @@ static void send_udp_frags(int fd_raw, struct sockaddr *addr,
while (offset < (UDP_HLEN + payload_len)) {
send_fragment(fd_raw, addr, alen, offset, ipv6);
/* IPv4 ignores duplicates, so randomly send a duplicate. */
- if (ipv4 && (1 == rand() % 100))
+ if (rand() % 100 == 1)
send_fragment(fd_raw, addr, alen, offset, ipv6);
offset += 2 * max_frag_len;
}
@@ -342,7 +340,7 @@ static void run_test(struct sockaddr *addr, socklen_t alen, bool ipv6)
*/
struct timeval tv = { .tv_sec = 1, .tv_usec = 10 };
int idx;
- int min_frag_len = ipv6 ? 1280 : 8;
+ int min_frag_len = 8;
/* Initialize the payload. */
for (idx = 0; idx < MSG_LEN_MAX; ++idx)
@@ -434,7 +432,7 @@ static void parse_opts(int argc, char **argv)
{
int c;
- while ((c = getopt(argc, argv, "46ov")) != -1) {
+ while ((c = getopt(argc, argv, "46opv")) != -1) {
switch (c) {
case '4':
cfg_do_ipv4 = true;
@@ -445,6 +443,9 @@ static void parse_opts(int argc, char **argv)
case 'o':
cfg_overlap = true;
break;
+ case 'p':
+ cfg_permissive = true;
+ break;
case 'v':
cfg_verbose = true;
break;
diff --git a/tools/testing/selftests/net/ip_defrag.sh b/tools/testing/selftests/net/ip_defrag.sh
index 7dd79a9efb17..15d3489ecd9c 100755
--- a/tools/testing/selftests/net/ip_defrag.sh
+++ b/tools/testing/selftests/net/ip_defrag.sh
@@ -20,6 +20,10 @@ setup() {
ip netns exec "${NETNS}" sysctl -w net.ipv6.ip6frag_low_thresh=7000000 >/dev/null 2>&1
ip netns exec "${NETNS}" sysctl -w net.ipv6.ip6frag_time=1 >/dev/null 2>&1
+ ip netns exec "${NETNS}" sysctl -w net.netfilter.nf_conntrack_frag6_high_thresh=9000000 >/dev/null 2>&1
+ ip netns exec "${NETNS}" sysctl -w net.netfilter.nf_conntrack_frag6_low_thresh=7000000 >/dev/null 2>&1
+ ip netns exec "${NETNS}" sysctl -w net.netfilter.nf_conntrack_frag6_timeout=1 >/dev/null 2>&1
+
# DST cache can get full with a lot of frags, with GC not keeping up with the test.
ip netns exec "${NETNS}" sysctl -w net.ipv6.route.max_size=65536 >/dev/null 2>&1
}
@@ -43,4 +47,16 @@ ip netns exec "${NETNS}" ./ip_defrag -6
echo "ipv6 defrag with overlaps"
ip netns exec "${NETNS}" ./ip_defrag -6o
+# insert an nf_conntrack rule so that the codepath in nf_conntrack_reasm.c taken
+ip netns exec "${NETNS}" ip6tables -A INPUT -m conntrack --ctstate INVALID -j ACCEPT
+
+echo "ipv6 nf_conntrack defrag"
+ip netns exec "${NETNS}" ./ip_defrag -6
+
+echo "ipv6 nf_conntrack defrag with overlaps"
+# netfilter will drop some invalid packets, so we run the test in
+# permissive mode: i.e. pass the test if the packet is correctly assembled
+# even if we sent an overlap
+ip netns exec "${NETNS}" ./ip_defrag -6op
+
echo "all tests done"
--
2.20.1.321.g9e740568ce-goog
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