selftests/bpf: remove xdp_synproxy IP_DF check

In real world production websites, the IP_DF flag is not always set for each packet from these websites. the IP_DF flag check breaks Internet connection to these websites for home based firewall like BPFire when XDP synproxy program is attached to firewall Internet facing side interface. see [0] [0] vincentmli/BPFire#59 Signed-off-by: Vincent Li <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Martin KaFai Lau <[email protected]>
kernel-patches · Oct 29, 2024 · 0ab7cd1 · 0ab7cd1
1 parent 97e9053
commit 0ab7cd1
Showing 1 changed file with 1 addition and 2 deletions.
diff --git a/tools/testing/selftests/bpf/progs/xdp_synproxy_kern.c b/tools/testing/selftests/bpf/progs/xdp_synproxy_kern.c
@@ -21,7 +21,6 @@
 
 #define tcp_flag_word(tp) (((union tcp_word_hdr *)(tp))->words[3])
 
-#define IP_DF 0x4000
 #define IP_MF 0x2000
 #define IP_OFFSET 0x1fff
 
@@ -442,7 +441,7 @@ static __always_inline int tcp_lookup(void *ctx, struct header_pointers *hdr, bo
 		/* TCP doesn't normally use fragments, and XDP can't reassemble
 		 * them.
 		 */
-		if ((hdr->ipv4->frag_off & bpf_htons(IP_DF | IP_MF | IP_OFFSET)) != bpf_htons(IP_DF))
+		if ((hdr->ipv4->frag_off & bpf_htons(IP_MF | IP_OFFSET)) != 0)
 			return XDP_DROP;
 
 		tup.ipv4.saddr = hdr->ipv4->saddr;