icmpv6.c: Move code generating ipv6 hdr to its own function
It will be re-used in next commits.
Change-Id: I3c108efad6461cd4e82ef435290005174bc8b30e
diff --git a/lib/icmpv6.c b/lib/icmpv6.c
index 804a212..ae72b4c 100644
--- a/lib/icmpv6.c
+++ b/lib/icmpv6.c
@@ -90,6 +90,30 @@
uint32_t res2;
uint8_t prefix[16];
} __attribute__ ((packed));
+/* Prepends the ipv6 header and returns checksum content */
+static uint16_t icmpv6_prepend_ip6hdr(struct msgb *msg, const struct in6_addr *saddr,
+ const struct in6_addr *daddr)
+{
+ uint32_t len;
+ uint16_t skb_csum;
+ struct ip6_hdr *i6h;
+
+ /* checksum */
+ skb_csum = csum_partial(msgb_data(msg), msgb_length(msg), 0);
+ len = msgb_length(msg);
+ skb_csum = csum_ipv6_magic(saddr, daddr, len, IPPROTO_ICMPV6, skb_csum);
+
+ /* Push IPv6 header in front of ICMPv6 packet */
+ i6h = (struct ip6_hdr *) msgb_push(msg, sizeof(*i6h));
+ /* 4 bits version, 8 bits TC, 20 bits flow-ID */
+ i6h->ip6_ctlun.ip6_un1.ip6_un1_flow = htonl(0x60000000);
+ i6h->ip6_ctlun.ip6_un1.ip6_un1_plen = htons(len);
+ i6h->ip6_ctlun.ip6_un1.ip6_un1_nxt = IPPROTO_ICMPV6;
+ i6h->ip6_ctlun.ip6_un1.ip6_un1_hlim = 255;
+ i6h->ip6_src = *saddr;
+ i6h->ip6_dst = *daddr;
+ return skb_csum;
+}
/*! construct a 3GPP 29.061 compliant router advertisement for a given prefix
@@ -104,9 +128,6 @@
struct msgb *msg = msgb_alloc_headroom(512,128, "IPv6 RA");
struct icmpv6_radv_hdr *ra;
struct icmpv6_opt_prefix *ra_opt_pref;
- struct ip6_hdr *i6h;
- uint32_t len;
- uint16_t skb_csum;
OSMO_ASSERT(msg);
@@ -144,19 +165,7 @@
memcpy(ra_opt_pref->prefix, prefix, sizeof(ra_opt_pref->prefix));
/* checksum */
- skb_csum = csum_partial(msgb_data(msg), msgb_length(msg), 0);
- len = msgb_length(msg);
- ra->hdr.csum = csum_ipv6_magic(saddr, daddr, len, IPPROTO_ICMPV6, skb_csum);
-
- /* Push IPv6 header in front of ICMPv6 packet */
- i6h = (struct ip6_hdr *) msgb_push(msg, sizeof(*i6h));
- /* 4 bits version, 8 bits TC, 20 bits flow-ID */
- i6h->ip6_ctlun.ip6_un1.ip6_un1_flow = htonl(0x60000000);
- i6h->ip6_ctlun.ip6_un1.ip6_un1_plen = htons(len);
- i6h->ip6_ctlun.ip6_un1.ip6_un1_nxt = IPPROTO_ICMPV6;
- i6h->ip6_ctlun.ip6_un1.ip6_un1_hlim = 255;
- i6h->ip6_src = *saddr;
- i6h->ip6_dst = *daddr;
+ ra->hdr.csum = icmpv6_prepend_ip6hdr(msg, saddr, daddr);
return msg;
}