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tap: Simplify some casts in the tap "slow path" functions

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We can both remove some variables which differ from others only in type,
and slightly improve type safety.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
David Gibson 2024-03-08 17:53:23 +11:00 committed by Stefano Brivio
parent 2d0e0084b6
commit 1ebe787fe4
1 changed files with 18 additions and 23 deletions
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41
tap.c
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@ -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 * 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, static void *tap_push_ip4h(struct iphdr *ip4h, struct in_addr src,
size_t len, uint8_t proto) struct in_addr dst, size_t len, uint8_t proto)
{ {
struct iphdr *ip4h = (struct iphdr *)buf;
ip4h->version = 4; ip4h->version = 4;
ip4h->ihl = sizeof(struct iphdr) / 4; ip4h->ihl = sizeof(struct iphdr) / 4;
ip4h->tos = 0; 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); size_t udplen = len + sizeof(struct udphdr);
char buf[USHRT_MAX]; char buf[USHRT_MAX];
void *ip4h = tap_push_l2h(c, buf, ETH_P_IP); struct iphdr *ip4h = tap_push_l2h(c, buf, ETH_P_IP);
void *uhp = tap_push_ip4h(ip4h, src, dst, udplen, IPPROTO_UDP); struct udphdr *uh = tap_push_ip4h(ip4h, src, dst, udplen, IPPROTO_UDP);
struct udphdr *uh = (struct udphdr *)uhp;
char *data = (char *)(uh + 1); char *data = (char *)(uh + 1);
uh->source = htons(sport); 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) const void *in, size_t len)
{ {
char buf[USHRT_MAX]; char buf[USHRT_MAX];
void *ip4h = tap_push_l2h(c, buf, ETH_P_IP); struct iphdr *ip4h = tap_push_l2h(c, buf, ETH_P_IP);
char *data = tap_push_ip4h(ip4h, src, dst, len, IPPROTO_ICMP); struct icmphdr *icmp4h = tap_push_ip4h(ip4h, src, dst,
struct icmphdr *icmp4h = (struct icmphdr *)data; len, IPPROTO_ICMP);
memcpy(data, in, len); memcpy(icmp4h, in, len);
csum_icmp4(icmp4h, icmp4h + 1, len - sizeof(*icmp4h)); 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); 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 * 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 *src,
const struct in6_addr *dst, const struct in6_addr *dst,
size_t len, uint8_t proto, uint32_t flow) size_t len, uint8_t proto, uint32_t flow)
{ {
struct ipv6hdr *ip6h = (struct ipv6hdr *)buf;
ip6h->payload_len = htons(len); ip6h->payload_len = htons(len);
ip6h->priority = 0; ip6h->priority = 0;
ip6h->version = 6; ip6h->version = 6;
@ -268,9 +263,9 @@ void tap_udp6_send(const struct ctx *c,
{ {
size_t udplen = len + sizeof(struct udphdr); size_t udplen = len + sizeof(struct udphdr);
char buf[USHRT_MAX]; char buf[USHRT_MAX];
void *ip6h = tap_push_l2h(c, buf, ETH_P_IPV6); struct ipv6hdr *ip6h = tap_push_l2h(c, buf, ETH_P_IPV6);
void *uhp = tap_push_ip6h(ip6h, src, dst, udplen, IPPROTO_UDP, flow); struct udphdr *uh = tap_push_ip6h(ip6h, src, dst,
struct udphdr *uh = (struct udphdr *)uhp; udplen, IPPROTO_UDP, flow);
char *data = (char *)(uh + 1); char *data = (char *)(uh + 1);
uh->source = htons(sport); uh->source = htons(sport);
@ -296,14 +291,14 @@ void tap_icmp6_send(const struct ctx *c,
const void *in, size_t len) const void *in, size_t len)
{ {
char buf[USHRT_MAX]; char buf[USHRT_MAX];
void *ip6h = tap_push_l2h(c, buf, ETH_P_IPV6); struct ipv6hdr *ip6h = tap_push_l2h(c, buf, ETH_P_IPV6);
char *data = tap_push_ip6h(ip6h, src, dst, len, IPPROTO_ICMPV6, 0); struct icmp6hdr *icmp6h = tap_push_ip6h(ip6h, src, dst, len,
struct icmp6hdr *icmp6h = (struct icmp6hdr *)data; IPPROTO_ICMPV6, 0);
memcpy(data, in, len); memcpy(icmp6h, in, len);
csum_icmp6(icmp6h, src, dst, icmp6h + 1, len - sizeof(*icmp6h)); 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); debug("tap: failed to send %zu bytes (IPv6)", len);
} }