We can both remove some variables which differ from others only in type,
and slightly improve type safety.
Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au>
---
tap.c | 41 ++++++++++++++++++-----------------------
1 file changed, 18 insertions(+), 23 deletions(-)
diff --git a/tap.c b/tap.c
index f9e2a8d9..38965842 100644
--- a/tap.c
+++ b/tap.c
@@ -146,11 +146,9 @@ static void *tap_push_l2h(const struct ctx *c, void *buf, uint16_t
proto)
*
* Return: pointer at which to write the packet's payload
*/
-static void *tap_push_ip4h(char *buf, struct in_addr src, struct in_addr dst,
- size_t len, uint8_t proto)
+static void *tap_push_ip4h(struct iphdr *ip4h, struct in_addr src,
+ struct in_addr dst, size_t len, uint8_t proto)
{
- struct iphdr *ip4h = (struct iphdr *)buf;
-
ip4h->version = 4;
ip4h->ihl = sizeof(struct iphdr) / 4;
ip4h->tos = 0;
@@ -181,9 +179,8 @@ void tap_udp4_send(const struct ctx *c, struct in_addr src, in_port_t
sport,
{
size_t udplen = len + sizeof(struct udphdr);
char buf[USHRT_MAX];
- void *ip4h = tap_push_l2h(c, buf, ETH_P_IP);
- void *uhp = tap_push_ip4h(ip4h, src, dst, udplen, IPPROTO_UDP);
- struct udphdr *uh = (struct udphdr *)uhp;
+ struct iphdr *ip4h = tap_push_l2h(c, buf, ETH_P_IP);
+ struct udphdr *uh = tap_push_ip4h(ip4h, src, dst, udplen, IPPROTO_UDP);
char *data = (char *)(uh + 1);
uh->source = htons(sport);
@@ -208,14 +205,14 @@ void tap_icmp4_send(const struct ctx *c, struct in_addr src, struct
in_addr dst,
const void *in, size_t len)
{
char buf[USHRT_MAX];
- void *ip4h = tap_push_l2h(c, buf, ETH_P_IP);
- char *data = tap_push_ip4h(ip4h, src, dst, len, IPPROTO_ICMP);
- struct icmphdr *icmp4h = (struct icmphdr *)data;
+ struct iphdr *ip4h = tap_push_l2h(c, buf, ETH_P_IP);
+ struct icmphdr *icmp4h = tap_push_ip4h(ip4h, src, dst,
+ len, IPPROTO_ICMP);
- memcpy(data, in, len);
+ memcpy(icmp4h, in, len);
csum_icmp4(icmp4h, icmp4h + 1, len - sizeof(*icmp4h));
- if (tap_send(c, buf, len + (data - buf)) < 0)
+ if (tap_send(c, buf, len + ((char *)icmp4h - buf)) < 0)
debug("tap: failed to send %zu bytes (IPv4)", len);
}
@@ -230,13 +227,11 @@ void tap_icmp4_send(const struct ctx *c, struct in_addr src, struct
in_addr dst,
*
* Return: pointer at which to write the packet's payload
*/
-static void *tap_push_ip6h(char *buf,
+static void *tap_push_ip6h(struct ipv6hdr *ip6h,
const struct in6_addr *src,
const struct in6_addr *dst,
size_t len, uint8_t proto, uint32_t flow)
{
- struct ipv6hdr *ip6h = (struct ipv6hdr *)buf;
-
ip6h->payload_len = htons(len);
ip6h->priority = 0;
ip6h->version = 6;
@@ -268,9 +263,9 @@ void tap_udp6_send(const struct ctx *c,
{
size_t udplen = len + sizeof(struct udphdr);
char buf[USHRT_MAX];
- void *ip6h = tap_push_l2h(c, buf, ETH_P_IPV6);
- void *uhp = tap_push_ip6h(ip6h, src, dst, udplen, IPPROTO_UDP, flow);
- struct udphdr *uh = (struct udphdr *)uhp;
+ struct ipv6hdr *ip6h = tap_push_l2h(c, buf, ETH_P_IPV6);
+ struct udphdr *uh = tap_push_ip6h(ip6h, src, dst,
+ udplen, IPPROTO_UDP, flow);
char *data = (char *)(uh + 1);
uh->source = htons(sport);
@@ -296,14 +291,14 @@ void tap_icmp6_send(const struct ctx *c,
const void *in, size_t len)
{
char buf[USHRT_MAX];
- void *ip6h = tap_push_l2h(c, buf, ETH_P_IPV6);
- char *data = tap_push_ip6h(ip6h, src, dst, len, IPPROTO_ICMPV6, 0);
- struct icmp6hdr *icmp6h = (struct icmp6hdr *)data;
+ struct ipv6hdr *ip6h = tap_push_l2h(c, buf, ETH_P_IPV6);
+ struct icmp6hdr *icmp6h = tap_push_ip6h(ip6h, src, dst, len,
+ IPPROTO_ICMPV6, 0);
- memcpy(data, in, len);
+ memcpy(icmp6h, in, len);
csum_icmp6(icmp6h, src, dst, icmp6h + 1, len - sizeof(*icmp6h));
- if (tap_send(c, buf, len + (data - buf)) < 1)
+ if (tap_send(c, buf, len + ((char *)icmp6h - buf)) < 1)
debug("tap: failed to send %zu bytes (IPv6)", len);
}
--
2.44.0