diff options
Diffstat (limited to 'tap.c')
| -rw-r--r-- | tap.c | 177 |
1 files changed, 94 insertions, 83 deletions
@@ -113,100 +113,111 @@ const struct in6_addr *tap_ip6_daddr(const struct ctx *c, } /** - * tap_ip_send() - Send IP packet, with L2 headers, calculating L3/L4 checksums + * tap_push_l2h() - Build an L2 header for an inbound packet * @c: Execution context - * @src: IPv6 source address, IPv4-mapped for IPv4 sources - * @proto: L4 protocol number - * @in: Payload - * @len: L4 payload length - * @flow: Flow label for TCP over IPv6 + * @buf: Buffer address at which to generate header + * @proto: Ethernet protocol number for L3 + * + * Return: pointer at which to write the packet's payload */ -void tap_ip_send(const struct ctx *c, const struct in6_addr *src, uint8_t proto, - const char *in, size_t len, uint32_t flow) +static void *tap_push_l2h(const struct ctx *c, void *buf, uint16_t proto) { - char buf[USHRT_MAX]; - struct ethhdr *eh; - - eh = (struct ethhdr *)buf; + struct ethhdr *eh = (struct ethhdr *)buf; /* TODO: ARP table lookup */ memcpy(eh->h_dest, c->mac_guest, ETH_ALEN); memcpy(eh->h_source, c->mac, ETH_ALEN); + eh->h_proto = ntohs(proto); + return eh + 1; +} - if (IN6_IS_ADDR_V4MAPPED(src)) { - struct iphdr *iph = (struct iphdr *)(eh + 1); - char *data = (char *)(iph + 1); - - eh->h_proto = ntohs(ETH_P_IP); - - iph->version = 4; - iph->ihl = 5; - iph->tos = 0; - iph->tot_len = htons(len + 20); - iph->id = 0; - iph->frag_off = 0; - iph->ttl = 255; - iph->protocol = proto; - iph->daddr = tap_ip4_daddr(c); - memcpy(&iph->saddr, &src->s6_addr[12], 4); - - csum_ip4_header(iph); - - memcpy(data, in, len); - - if (iph->protocol == IPPROTO_UDP) { - struct udphdr *uh = (struct udphdr *)(iph + 1); - - csum_udp4(uh, iph->saddr, iph->daddr, uh + 1, len - sizeof(*uh)); - } else if (iph->protocol == IPPROTO_ICMP) { - struct icmphdr *ih = (struct icmphdr *)(iph + 1); - csum_icmp4(ih, ih + 1, len - sizeof(*ih)); - } - - if (tap_send(c, buf, len + sizeof(*iph) + sizeof(*eh)) < 0) - debug("tap: failed to send %lu bytes (IPv4)", len); - } else { - struct ipv6hdr *ip6h = (struct ipv6hdr *)(eh + 1); - char *data = (char *)(ip6h + 1); - - eh->h_proto = ntohs(ETH_P_IPV6); - - memset(ip6h->flow_lbl, 0, 3); - ip6h->payload_len = htons(len); - ip6h->priority = 0; - - ip6h->saddr = *src; - ip6h->daddr = *tap_ip6_daddr(c, src); - - memcpy(data, in, len); - - ip6h->hop_limit = proto; - ip6h->version = 0; - ip6h->nexthdr = 0; - - if (proto == IPPROTO_UDP) { - struct udphdr *uh = (struct udphdr *)(ip6h + 1); - - csum_udp6(uh, &ip6h->saddr, &ip6h->daddr, - uh + 1, len - sizeof(*uh)); - } else if (proto == IPPROTO_ICMPV6) { - struct icmp6hdr *ih = (struct icmp6hdr *)(ip6h + 1); +/** + * tap_ip4_send() - Send IPv4 packet, with L2 headers, calculating L3/L4 checksums + * @c: Execution context + * @src: IPv4 source address + * @proto: L4 protocol number + * @in: Payload + * @len: L4 payload length + */ +void tap_ip4_send(const struct ctx *c, in_addr_t src, uint8_t proto, + const char *in, size_t len) +{ + char buf[USHRT_MAX]; + struct iphdr *ip4h = (struct iphdr *)tap_push_l2h(c, buf, ETH_P_IP); + char *data = (char *)(ip4h + 1); + + ip4h->version = 4; + ip4h->ihl = sizeof(struct iphdr) / 4; + ip4h->tos = 0; + ip4h->tot_len = htons(len + sizeof(*ip4h)); + ip4h->id = 0; + ip4h->frag_off = 0; + ip4h->ttl = 255; + ip4h->protocol = proto; + ip4h->saddr = src; + ip4h->daddr = tap_ip4_daddr(c); + csum_ip4_header(ip4h); + + memcpy(data, in, len); + + if (ip4h->protocol == IPPROTO_UDP) { + struct udphdr *uh = (struct udphdr *)(ip4h + 1); + + csum_udp4(uh, ip4h->saddr, ip4h->daddr, + uh + 1, len - sizeof(*uh)); + } else if (ip4h->protocol == IPPROTO_ICMP) { + struct icmphdr *ih = (struct icmphdr *)(ip4h + 1); + csum_icmp4(ih, ih + 1, len - sizeof(*ih)); + } - csum_icmp6(ih, &ip6h->saddr, &ip6h->daddr, - ih + 1, len - sizeof(*ih)); - } - ip6h->version = 6; - ip6h->nexthdr = proto; - ip6h->hop_limit = 255; - if (flow) { - ip6h->flow_lbl[0] = (flow >> 16) & 0xf; - ip6h->flow_lbl[1] = (flow >> 8) & 0xff; - ip6h->flow_lbl[2] = (flow >> 0) & 0xff; - } + if (tap_send(c, buf, len + (data - buf)) < 0) + debug("tap: failed to send %lu bytes (IPv4)", len); +} - if (tap_send(c, buf, len + sizeof(*ip6h) + sizeof(*eh)) < 1) - debug("tap: failed to send %lu bytes (IPv6)", len); +/** + * tap_ip6_send() - Send IPv6 packet, with L2 headers, calculating L3/L4 checksums + * @c: Execution context + * @src: IPv6 source address + * @proto: L4 protocol number + * @in: Payload + * @len: L4 payload length + * @flow: Flow label + */ +void tap_ip6_send(const struct ctx *c, const struct in6_addr *src, + uint8_t proto, const char *in, size_t len, uint32_t flow) +{ + char buf[USHRT_MAX]; + struct ipv6hdr *ip6h = + (struct ipv6hdr *)tap_push_l2h(c, buf, ETH_P_IPV6); + char *data = (char *)(ip6h + 1); + + ip6h->payload_len = htons(len); + ip6h->priority = 0; + ip6h->version = 6; + ip6h->nexthdr = proto; + ip6h->hop_limit = 255; + ip6h->saddr = *src; + ip6h->daddr = *tap_ip6_daddr(c, src); + ip6h->flow_lbl[0] = (flow >> 16) & 0xf; + ip6h->flow_lbl[1] = (flow >> 8) & 0xff; + ip6h->flow_lbl[2] = (flow >> 0) & 0xff; + + memcpy(data, in, len); + + if (proto == IPPROTO_UDP) { + struct udphdr *uh = (struct udphdr *)(ip6h + 1); + + csum_udp6(uh, &ip6h->saddr, &ip6h->daddr, + uh + 1, len - sizeof(*uh)); + } else if (proto == IPPROTO_ICMPV6) { + struct icmp6hdr *ih = (struct icmp6hdr *)(ip6h + 1); + + csum_icmp6(ih, &ip6h->saddr, &ip6h->daddr, + ih + 1, len - sizeof(*ih)); } + + if (tap_send(c, buf, len + (data - buf)) < 1) + debug("tap: failed to send %lu bytes (IPv6)", len); } PACKET_POOL_DECL(pool_l4, UIO_MAXIOV, pkt_buf); |