selftests/bpf: Fix misaligned memory accesses in xdp_bonding test

Construct packet buffer explicitly for each packet to avoid unaligned
memory accesses.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211124002325.1737739-13-andrii@kernel.org

diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_bonding.c b/tools/testing/selftests/bpf/prog_tests/xdp_bonding.c
index faa22b8..5e3a26b 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/xdp_bonding.c
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_bonding.c
@@ -218,9 +218,9 @@ static int send_udp_packets(int vary_dst_ip)
                .h_dest = BOND2_MAC,
                .h_proto = htons(ETH_P_IP),
        };
-       uint8_t buf[128] = {};
-       struct iphdr *iph = (struct iphdr *)(buf + sizeof(eh));
-       struct udphdr *uh = (struct udphdr *)(buf + sizeof(eh) + sizeof(*iph));
+       struct iphdr iph = {};
+       struct udphdr uh = {};
+       uint8_t buf[128];
        int i, s = -1;
        int ifindex;
 
@@ -232,17 +232,16 @@ static int send_udp_packets(int vary_dst_ip)
        if (!ASSERT_GT(ifindex, 0, "get bond1 ifindex"))
                goto err;
 
-       memcpy(buf, &eh, sizeof(eh));
-       iph->ihl = 5;
-       iph->version = 4;
-       iph->tos = 16;
-       iph->id = 1;
-       iph->ttl = 64;
-       iph->protocol = IPPROTO_UDP;
-       iph->saddr = 1;
-       iph->daddr = 2;
-       iph->tot_len = htons(sizeof(buf) - ETH_HLEN);
-       iph->check = 0;
+       iph.ihl = 5;
+       iph.version = 4;
+       iph.tos = 16;
+       iph.id = 1;
+       iph.ttl = 64;
+       iph.protocol = IPPROTO_UDP;
+       iph.saddr = 1;
+       iph.daddr = 2;
+       iph.tot_len = htons(sizeof(buf) - ETH_HLEN);
+       iph.check = 0;
 
        for (i = 1; i <= NPACKETS; i++) {
                int n;
@@ -253,10 +252,15 @@ static int send_udp_packets(int vary_dst_ip)
                };
 
                /* vary the UDP destination port for even distribution with roundrobin/xor modes */
-               uh->dest++;
+               uh.dest++;
 
                if (vary_dst_ip)
-                       iph->daddr++;
+                       iph.daddr++;
+
+               /* construct a packet */
+               memcpy(buf, &eh, sizeof(eh));
+               memcpy(buf + sizeof(eh), &iph, sizeof(iph));
+               memcpy(buf + sizeof(eh) + sizeof(iph), &uh, sizeof(uh));
 
                n = sendto(s, buf, sizeof(buf), 0, (struct sockaddr *)&saddr_ll, sizeof(saddr_ll));
                if (!ASSERT_EQ(n, sizeof(buf), "sendto"))