commit 242af3942595ac48eac7dd73dcf15250185a59bd
author Maciej Żenczykowski <maze@google.com> Mon Aug 22 09:11:10 2022 +0000
committer Maciej Żenczykowski <maze@google.com> Mon Aug 22 09:12:26 2022 +0000
tree 737c5804602e570ddf21a2b9b3483ece4036b863
parent 56dca4119a34a1a06460b9432a0bfa612b4ab98b

dscpPolicy.c - old/new_first_u32 is actually be32

Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I10b19a010000f1f49c2a48448f413376045bfe1f

bpf_progs/dscpPolicy.c

diff --git a/bpf_progs/dscpPolicy.c b/bpf_progs/dscpPolicy.c
index 3e4456f..72f63c6 100644
--- a/bpf_progs/dscpPolicy.c
+++ b/bpf_progs/dscpPolicy.c
@@ -62,8 +62,8 @@
     uint8_t protocol = 0;  // TODO: Use are reserved value? Or int (-1) and cast to uint below?
     struct in6_addr src_ip = {};
     struct in6_addr dst_ip = {};
-    uint8_t tos = 0;             // Only used for IPv4
-    uint32_t old_first_u32 = 0;  // Only used for IPv6
+    uint8_t tos = 0;            // Only used for IPv4
+    __be32 old_first_be32 = 0;  // Only used for IPv6
     if (ipv4) {
         const struct iphdr* const iph = (void*)(eth + 1);
         hdr_size = l2_header_size + sizeof(struct iphdr);
@@ -96,7 +96,7 @@
         src_ip = ip6h->saddr;
         dst_ip = ip6h->daddr;
         protocol = ip6h->nexthdr;
-        old_first_u32 = *(uint32_t*)ip6h;
+        old_first_be32 = *(__be32*)ip6h;
     }
 
     switch (protocol) {
@@ -135,9 +135,9 @@
                                 sizeof(uint16_t));
             bpf_skb_store_bytes(skb, IP4_OFFSET(tos, l2_header_size), &newTos, sizeof(newTos), 0);
         } else {
-            uint32_t new_first_u32 =
-                htonl(ntohl(old_first_u32) & 0xF03FFFFF | (existing_rule->dscp_val << 22));
-            bpf_skb_store_bytes(skb, l2_header_size, &new_first_u32, sizeof(uint32_t),
+            __be32 new_first_be32 =
+                htonl(ntohl(old_first_be32) & 0xF03FFFFF | (existing_rule->dscp_val << 22));
+            bpf_skb_store_bytes(skb, l2_header_size, &new_first_be32, sizeof(__be32),
                 BPF_F_RECOMPUTE_CSUM);
         }
         return;
@@ -214,8 +214,8 @@
         bpf_l3_csum_replace(skb, IP4_OFFSET(check, l2_header_size), htons(tos), htons(new_tos), 2);
         bpf_skb_store_bytes(skb, IP4_OFFSET(tos, l2_header_size), &new_tos, sizeof(new_tos), 0);
     } else {
-        uint32_t new_first_u32 = htonl(ntohl(old_first_u32) & 0xF03FFFFF | (new_dscp << 22));
-        bpf_skb_store_bytes(skb, l2_header_size, &new_first_u32, sizeof(uint32_t),
+        __be32 new_first_be32 = htonl(ntohl(old_first_be32) & 0xF03FFFFF | (new_dscp << 22));
+        bpf_skb_store_bytes(skb, l2_header_size, &new_first_be32, sizeof(__be32),
             BPF_F_RECOMPUTE_CSUM);
     }
     return;