[PATCH net-next 3/3] selftests/net: fix GRO coalesce test and add ext

Richard Gobert
2023-12-21T18:59:30Z

Currently there is no test which checks that IPv6 extension header packets
successfully coalesce. This commit adds a test, which verifies two IPv6
packets with HBH extension headers do coalesce.

I changed the receive socket filter to accept a packet with one extension
header. This change exposed a bug in the fragment test -- the old BPF did
not accept the fragment packet. I updated correct_num_packets in the
fragment test accordingly.

Signed-off-by: Richard Gobert <richardbgobert@gmail.com>
---
tools/testing/selftests/net/gro.c | 78 ++++++++++++++++++++++++++++---
1 file changed, 71 insertions(+), 7 deletions(-)

diff --git a/tools/testing/selftests/net/gro.c b/tools/testing/selftests/net/gro.c
index 30024d0ed373..4ee34dca8e5f 100644
--- a/tools/testing/selftests/net/gro.c
+++ b/tools/testing/selftests/net/gro.c
@@ -71,6 +71,10 @@
#define MAX_PAYLOAD (IP_MAXPACKET - sizeof(struct tcphdr) - sizeof(struct ipv6hdr))
#define NUM_LARGE_PKT (MAX_PAYLOAD / MSS)
#define MAX_HDR_LEN (ETH_HLEN + sizeof(struct ipv6hdr) + sizeof(struct tcphdr))
+#define MIN_EXTHDR_SIZE 8 /* minimum size of IPv6 extension header */
+
+#define ipv6_optlen(p) (((p)->hdrlen+1) << 3) /* calculate IPv6 extension header len */
+

static const char *addr6_src = "fdaa::2";
static const char *addr6_dst = "fdaa::1";
@@ -104,7 +108,7 @@ static void setup_sock_filter(int fd)
const int dport_off = tcp_offset + offsetof(struct tcphdr, dest);
const int ethproto_off = offsetof(struct ethhdr, h_proto);
int optlen = 0;
- int ipproto_off;
+ int ipproto_off, opt_ipproto_off;
int next_off;

if (proto == PF_INET)
@@ -116,14 +120,27 @@ static void setup_sock_filter(int fd)
if (strcmp(testname, "ip") == 0) {
if (proto == PF_INET)
optlen = sizeof(struct ip_timestamp);
- else
- optlen = sizeof(struct ip6_frag);
+ else {
+ // same size for HBH and Fragment extension header types
+ optlen = MIN_EXTHDR_SIZE;
+ opt_ipproto_off = ETH_HLEN + sizeof(struct ipv6hdr) +
+ offsetof(struct ip6_ext, ip6e_nxt);
+ }
}

+ /*
+ * this filter validates the following:
+ * - packet is IPv4/IPv6 according to the running test.
+ * - packet is TCP. Also handles the case of one extension header and then TCP.
+ * - checks the packet tcp dport equals to DPORT.
+ * (also handles the case of one extension header and then TCP.)
+ */
struct sock_filter filter[] = {
BPF_STMT(BPF_LD + BPF_H + BPF_ABS, ethproto_off),
- BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ntohs(ethhdr_proto), 0, 7),
+ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ntohs(ethhdr_proto), 0, 9),
BPF_STMT(BPF_LD + BPF_B + BPF_ABS, ipproto_off),
+ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_TCP, 2, 0),
+ BPF_STMT(BPF_LD + BPF_B + BPF_ABS, opt_ipproto_off),
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_TCP, 0, 5),
BPF_STMT(BPF_LD + BPF_H + BPF_ABS, dport_off),
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DPORT, 2, 0),
@@ -576,6 +593,39 @@ static void add_ipv4_ts_option(void *buf, void *optpkt)
iph->check = checksum_fold(iph, sizeof(struct iphdr) + optlen, 0);
}

+static void add_ipv6_exthdr(void *buf, void *optpkt, __u8 exthdr_type)
+{
+ struct ipv6_opt_hdr *hbh_hdr = (struct ipv6_opt_hdr *)(optpkt + tcp_offset);
+ struct ipv6hdr *iph = (struct ipv6hdr *)(optpkt + ETH_HLEN);
+ int opt_len;
+
+ hbh_hdr->hdrlen = 0;
+ hbh_hdr->nexthdr = IPPROTO_TCP;
+ opt_len = ipv6_optlen(hbh_hdr);
+
+ memcpy(optpkt, buf, tcp_offset);
+ memcpy(optpkt + tcp_offset + MIN_EXTHDR_SIZE, buf + tcp_offset,
+ sizeof(struct tcphdr) + PAYLOAD_LEN);
+
+ iph->nexthdr = exthdr_type;
+ iph->payload_len = htons(ntohs(iph->payload_len) + MIN_EXTHDR_SIZE);
+}
+
+/* Send IPv6 packet with extension header */
+static void send_ipv6_exthdr(int fd, struct sockaddr_ll *daddr)
+{
+ static char buf[MAX_HDR_LEN + PAYLOAD_LEN];
+ static char exthdr_pck[sizeof(buf) + MIN_EXTHDR_SIZE];
+
+ create_packet(buf, 0, 0, PAYLOAD_LEN, 0);
+ add_ipv6_exthdr(buf, exthdr_pck, IPPROTO_HOPOPTS);
+ write_packet(fd, exthdr_pck, total_hdr_len + PAYLOAD_LEN + MIN_EXTHDR_SIZE, daddr);
+
+ create_packet(buf, PAYLOAD_LEN * 1, 0, PAYLOAD_LEN, 0);
+ add_ipv6_exthdr(buf, exthdr_pck, IPPROTO_HOPOPTS);
+ write_packet(fd, exthdr_pck, total_hdr_len + PAYLOAD_LEN + MIN_EXTHDR_SIZE, daddr);
+}
+
/* IPv4 options shouldn't coalesce */
static void send_ip_options(int fd, struct sockaddr_ll *daddr)
{
@@ -697,7 +747,7 @@ static void send_fragment6(int fd, struct sockaddr_ll *daddr)
create_packet(buf, PAYLOAD_LEN * i, 0, PAYLOAD_LEN, 0);
write_packet(fd, buf, bufpkt_len, daddr);
}
-
+ sleep(1);
create_packet(buf, PAYLOAD_LEN * 2, 0, PAYLOAD_LEN, 0);
memset(extpkt, 0, extpkt_len);

@@ -760,6 +810,7 @@ static void check_recv_pkts(int fd, int *correct_payload,
vlog("}, Total %d packets\nReceived {", correct_num_pkts);

while (1) {
+ ip_ext_len = 0;
pkt_size = recv(fd, buffer, IP_MAXPACKET + ETH_HLEN + 1, 0);
if (pkt_size < 0)
error(1, errno, "could not receive");
@@ -767,7 +818,7 @@ static void check_recv_pkts(int fd, int *correct_payload,
if (iph->version == 4)
ip_ext_len = (iph->ihl - 5) * 4;
else if (ip6h->version == 6 && ip6h->nexthdr != IPPROTO_TCP)
- ip_ext_len = sizeof(struct ip6_frag);
+ ip_ext_len = MIN_EXTHDR_SIZE;

tcph = (struct tcphdr *)(buffer + tcp_offset + ip_ext_len);

@@ -880,7 +931,14 @@ static void gro_sender(void)
sleep(1);
write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
} else if (proto == PF_INET6) {
+ sleep(1);
send_fragment6(txfd, &daddr);
+ sleep(1);
+ write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+
+ sleep(1);
+ send_ipv6_exthdr(txfd, &daddr);
+ sleep(1);
write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
}
} else if (strcmp(testname, "large") == 0) {
@@ -997,7 +1055,13 @@ static void gro_receiver(void)
*/
printf("fragmented ip6 doesn't coalesce: ");
correct_payload[0] = PAYLOAD_LEN * 2;
- check_recv_pkts(rxfd, correct_payload, 2);
+ correct_payload[1] = PAYLOAD_LEN;
+ correct_payload[2] = PAYLOAD_LEN;
+ check_recv_pkts(rxfd, correct_payload, 3);
+
+ correct_payload[0] = PAYLOAD_LEN * 2;
+ printf("ipv6 with extension header DOES coalesce: ");
+ check_recv_pkts(rxfd, correct_payload, 1);
}
} else if (strcmp(testname, "large") == 0) {
int offset = proto == PF_INET ? 20 : 0;
--
2.36.1