It is possible for drivers to generate xdp packets with data residing entirely in fragments. To keep parsing headers using direcy packet access, call bpf_xdp_pull_data() to pull headers into the linear data area. Signed-off-by: Amery Hung --- .../selftests/net/lib/xdp_native.bpf.c | 90 +++++++++++++++---- 1 file changed, 75 insertions(+), 15 deletions(-) diff --git a/tools/testing/selftests/net/lib/xdp_native.bpf.c b/tools/testing/selftests/net/lib/xdp_native.bpf.c index 521ba38f2ddd..68b2a08055ce 100644 --- a/tools/testing/selftests/net/lib/xdp_native.bpf.c +++ b/tools/testing/selftests/net/lib/xdp_native.bpf.c @@ -14,6 +14,9 @@ #define MAX_PAYLOAD_LEN 5000 #define MAX_HDR_LEN 64 +extern int bpf_xdp_pull_data(struct xdp_md *xdp, __u32 len, + __u64 flags) __ksym __weak; + enum { XDP_MODE = 0, XDP_PORT = 1, @@ -68,30 +71,57 @@ static void record_stats(struct xdp_md *ctx, __u32 stat_type) static struct udphdr *filter_udphdr(struct xdp_md *ctx, __u16 port) { - void *data_end = (void *)(long)ctx->data_end; - void *data = (void *)(long)ctx->data; struct udphdr *udph = NULL; - struct ethhdr *eth = data; + void *data, *data_end; + struct ethhdr *eth; + int err; + + err = bpf_xdp_pull_data(ctx, sizeof(*eth), 0); + if (err) + return NULL; + + data_end = (void *)(long)ctx->data_end; + data = eth = (void *)(long)ctx->data; if (data + sizeof(*eth) > data_end) return NULL; if (eth->h_proto == bpf_htons(ETH_P_IP)) { - struct iphdr *iph = data + sizeof(*eth); + struct iphdr *iph; + + err = bpf_xdp_pull_data(ctx, sizeof(*eth) + sizeof(*iph) + + sizeof(*udph), 0); + if (err) + return NULL; + + data_end = (void *)(long)ctx->data_end; + data = (void *)(long)ctx->data; + + iph = data + sizeof(*eth); if (iph + 1 > (struct iphdr *)data_end || iph->protocol != IPPROTO_UDP) return NULL; - udph = (void *)eth + sizeof(*iph) + sizeof(*eth); - } else if (eth->h_proto == bpf_htons(ETH_P_IPV6)) { - struct ipv6hdr *ipv6h = data + sizeof(*eth); + udph = data + sizeof(*iph) + sizeof(*eth); + } else if (eth->h_proto == bpf_htons(ETH_P_IPV6)) { + struct ipv6hdr *ipv6h; + + err = bpf_xdp_pull_data(ctx, sizeof(*eth) + sizeof(*ipv6h) + + sizeof(*udph), 0); + if (err) + return NULL; + + data_end = (void *)(long)ctx->data_end; + data = (void *)(long)ctx->data; + + ipv6h = data + sizeof(*eth); if (ipv6h + 1 > (struct ipv6hdr *)data_end || ipv6h->nexthdr != IPPROTO_UDP) return NULL; - udph = (void *)eth + sizeof(*ipv6h) + sizeof(*eth); + udph = data + sizeof(*ipv6h) + sizeof(*eth); } else { return NULL; } @@ -145,17 +175,34 @@ static void swap_machdr(void *data) static int xdp_mode_tx_handler(struct xdp_md *ctx, __u16 port) { - void *data_end = (void *)(long)ctx->data_end; - void *data = (void *)(long)ctx->data; struct udphdr *udph = NULL; - struct ethhdr *eth = data; + void *data, *data_end; + struct ethhdr *eth; + int err; + + err = bpf_xdp_pull_data(ctx, sizeof(*eth), 0); + if (err) + return XDP_PASS; + + data_end = (void *)(long)ctx->data_end; + data = eth = (void *)(long)ctx->data; if (data + sizeof(*eth) > data_end) return XDP_PASS; if (eth->h_proto == bpf_htons(ETH_P_IP)) { - struct iphdr *iph = data + sizeof(*eth); - __be32 tmp_ip = iph->saddr; + struct iphdr *iph; + __be32 tmp_ip; + + err = bpf_xdp_pull_data(ctx, sizeof(*eth) + sizeof(*iph) + + sizeof(*udph), 0); + if (err) + return XDP_PASS; + + data_end = (void *)(long)ctx->data_end; + data = (void *)(long)ctx->data; + + iph = data + sizeof(*eth); if (iph + 1 > (struct iphdr *)data_end || iph->protocol != IPPROTO_UDP) @@ -169,8 +216,10 @@ static int xdp_mode_tx_handler(struct xdp_md *ctx, __u16 port) return XDP_PASS; record_stats(ctx, STATS_RX); + eth = data; swap_machdr((void *)eth); + tmp_ip = iph->saddr; iph->saddr = iph->daddr; iph->daddr = tmp_ip; @@ -178,9 +227,19 @@ static int xdp_mode_tx_handler(struct xdp_md *ctx, __u16 port) return XDP_TX; - } else if (eth->h_proto == bpf_htons(ETH_P_IPV6)) { - struct ipv6hdr *ipv6h = data + sizeof(*eth); + } else if (eth->h_proto == bpf_htons(ETH_P_IPV6)) { struct in6_addr tmp_ipv6; + struct ipv6hdr *ipv6h; + + err = bpf_xdp_pull_data(ctx, sizeof(*eth) + sizeof(*ipv6h) + + sizeof(*udph), 0); + if (err) + return XDP_PASS; + + data_end = (void *)(long)ctx->data_end; + data = (void *)(long)ctx->data; + + ipv6h = data + sizeof(*eth); if (ipv6h + 1 > (struct ipv6hdr *)data_end || ipv6h->nexthdr != IPPROTO_UDP) @@ -194,6 +253,7 @@ static int xdp_mode_tx_handler(struct xdp_md *ctx, __u16 port) return XDP_PASS; record_stats(ctx, STATS_RX); + eth = data; swap_machdr((void *)eth); __builtin_memcpy(&tmp_ipv6, &ipv6h->saddr, sizeof(tmp_ipv6)); -- 2.47.3