diff options
Diffstat (limited to 'arp.c')
| -rw-r--r-- | arp.c | 51 |
1 files changed, 27 insertions, 24 deletions
@@ -30,53 +30,56 @@ #include "tap.h" /** - * arp() - Check if this is an ARP message, reply as needed + * arp() - Check if this is a supported ARP message, reply as needed * @c: Execution context - * @len: Total L2 packet length - * @eh: Packet buffer, Ethernet header + * @p: Packet pool, single packet with Ethernet buffer * - * Return: 0 if it's not an ARP message, 1 if handled, -1 on failure + * Return: 1 if handled, -1 on failure */ -int arp(struct ctx *c, struct ethhdr *eh, size_t len) +int arp(struct ctx *c, struct pool *p) { - struct arphdr *ah = (struct arphdr *)(eh + 1); - struct arpmsg *am = (struct arpmsg *)(ah + 1); unsigned char swap[4]; + struct ethhdr *eh; + struct arphdr *ah; + struct arpmsg *am; + size_t len; - if (eh->h_proto != htons(ETH_P_ARP)) - return 0; + eh = packet_get(p, 0, 0, sizeof(*eh), NULL); + ah = packet_get(p, 0, sizeof(*eh), sizeof(*ah), NULL); + am = packet_get(p, 0, sizeof(*eh) + sizeof(*ah), sizeof(*am), NULL); - if (len < sizeof(*eh) + sizeof(*ah) + sizeof(*am)) + if (!eh || !ah || !am) return -1; - if (ah->ar_hrd != htons(ARPHRD_ETHER) || - ah->ar_pro != htons(ETH_P_IP) || - ah->ar_hln != ETH_ALEN || ah->ar_pln != 4 || - ah->ar_op != htons(ARPOP_REQUEST)) + if (ah->ar_hrd != htons(ARPHRD_ETHER) || + ah->ar_pro != htons(ETH_P_IP) || + ah->ar_hln != ETH_ALEN || + ah->ar_pln != 4 || + ah->ar_op != htons(ARPOP_REQUEST)) return 1; /* Discard announcements (but not 0.0.0.0 "probes"): we might have the * same IP address, hide that. */ - if (memcmp(am->sip, (unsigned char[4]){ 0, 0, 0, 0 }, 4) && - !memcmp(am->sip, am->tip, 4)) + if (memcmp(am->sip, (unsigned char[4]){ 0 }, sizeof(am->tip)) && + !memcmp(am->sip, am->tip, sizeof(am->sip))) return 1; /* Don't resolve our own address, either. */ - if (!memcmp(am->tip, &c->addr4, 4)) + if (!memcmp(am->tip, &c->addr4, sizeof(am->tip))) return 1; ah->ar_op = htons(ARPOP_REPLY); - memcpy(am->tha, am->sha, ETH_ALEN); - memcpy(am->sha, c->mac, ETH_ALEN); + memcpy(am->tha, am->sha, sizeof(am->tha)); + memcpy(am->sha, c->mac, sizeof(am->sha)); - memcpy(swap, am->tip, 4); - memcpy(am->tip, am->sip, 4); - memcpy(am->sip, swap, 4); + memcpy(swap, am->tip, sizeof(am->tip)); + memcpy(am->tip, am->sip, sizeof(am->tip)); + memcpy(am->sip, swap, sizeof(am->sip)); len = sizeof(*eh) + sizeof(*ah) + sizeof(*am); - memcpy(eh->h_dest, eh->h_source, ETH_ALEN); - memcpy(eh->h_source, c->mac, ETH_ALEN); + memcpy(eh->h_dest, eh->h_source, sizeof(eh->h_dest)); + memcpy(eh->h_source, c->mac, sizeof(eh->h_source)); if (tap_send(c, eh, len, 0) < 0) perror("ARP: send"); |