a4d564ad7
Ken Sharp
2014-07-20
Subject
zcip: fix link-local IP conflict detection
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Commit Diff GitHub →
networking/zcip.c+22 -16
| @@ -366,11 +366,11 @@ int zcip_main(int argc UNUSED_PARAM, char **argv) | |
| nprobes++; | |
| VDBG("probe/%u %s@%s\n", | |
| nprobes, argv_intf, inet_ntoa(ip)); | |
| + | timeout_ms = PROBE_MIN * 1000; |
| + | timeout_ms += random_delay_ms(PROBE_MAX - PROBE_MIN); |
| arp(/* ARPOP_REQUEST, */ | |
| /* ð_addr, */ null_ip, | |
| &null_addr, ip); | |
| - | timeout_ms = PROBE_MIN * 1000; |
| - | timeout_ms += random_delay_ms(PROBE_MAX - PROBE_MIN); |
| } | |
| else { | |
| // Switch to announce state. | |
| @@ -378,10 +378,10 @@ int zcip_main(int argc UNUSED_PARAM, char **argv) | |
| nclaims = 0; | |
| VDBG("announce/%u %s@%s\n", | |
| nclaims, argv_intf, inet_ntoa(ip)); | |
| + | timeout_ms = ANNOUNCE_INTERVAL * 1000; |
| arp(/* ARPOP_REQUEST, */ | |
| /* ð_addr, */ ip, | |
| ð_addr, ip); | |
| - | timeout_ms = ANNOUNCE_INTERVAL * 1000; |
| } | |
| break; | |
| case RATE_LIMIT_PROBE: | |
| @@ -391,10 +391,10 @@ int zcip_main(int argc UNUSED_PARAM, char **argv) | |
| nclaims = 0; | |
| VDBG("announce/%u %s@%s\n", | |
| nclaims, argv_intf, inet_ntoa(ip)); | |
| + | timeout_ms = ANNOUNCE_INTERVAL * 1000; |
| arp(/* ARPOP_REQUEST, */ | |
| /* ð_addr, */ ip, | |
| ð_addr, ip); | |
| - | timeout_ms = ANNOUNCE_INTERVAL * 1000; |
| break; | |
| case ANNOUNCE: | |
| // timeouts in the ANNOUNCE state mean no conflicting ARP packets | |
| @@ -403,10 +403,10 @@ int zcip_main(int argc UNUSED_PARAM, char **argv) | |
| nclaims++; | |
| VDBG("announce/%u %s@%s\n", | |
| nclaims, argv_intf, inet_ntoa(ip)); | |
| + | timeout_ms = ANNOUNCE_INTERVAL * 1000; |
| arp(/* ARPOP_REQUEST, */ | |
| /* ð_addr, */ ip, | |
| ð_addr, ip); | |
| - | timeout_ms = ANNOUNCE_INTERVAL * 1000; |
| } | |
| else { | |
| // Switch to monitor state. | |
| @@ -495,22 +495,28 @@ int zcip_main(int argc UNUSED_PARAM, char **argv) | |
| } | |
| #endif | |
| if (p.arp.arp_op != htons(ARPOP_REQUEST) | |
| - | && p.arp.arp_op != htons(ARPOP_REPLY)) |
| + | && p.arp.arp_op != htons(ARPOP_REPLY) |
| + | ) { |
| continue; | |
| + | } |
| source_ip_conflict = 0; | |
| target_ip_conflict = 0; | |
| - | if (memcmp(p.arp.arp_spa, &ip.s_addr, sizeof(struct in_addr)) == 0 |
| - | && memcmp(&p.arp.arp_sha, ð_addr, ETH_ALEN) != 0 |
| - | ) { |
| - | source_ip_conflict = 1; |
| - | } |
| - | if (p.arp.arp_op == htons(ARPOP_REQUEST) |
| - | && memcmp(p.arp.arp_tpa, &ip.s_addr, sizeof(struct in_addr)) == 0 |
| - | && memcmp(&p.arp.arp_tha, ð_addr, ETH_ALEN) != 0 |
| - | ) { |
| - | target_ip_conflict = 1; |
| + | if (memcmp(&p.arp.arp_sha, ð_addr, ETH_ALEN) != 0) { |
| + | if (memcmp(p.arp.arp_spa, &ip.s_addr, sizeof(struct in_addr))) { |
| + | /* A probe or reply with source_ip == chosen ip */ |
| + | source_ip_conflict = 1; |
| + | } |
| + | if (p.arp.arp_op == htons(ARPOP_REQUEST) |
| + | && memcmp(p.arp.arp_spa, &null_ip, sizeof(struct in_addr)) == 0 |
| + | && memcmp(p.arp.arp_tpa, &ip.s_addr, sizeof(struct in_addr)) == 0 |
| + | ) { |
| + | /* A probe with source_ip == 0.0.0.0, target_ip == chosen ip: |
| + | * another host trying to claim this ip! |
| + | */ |
| + | target_ip_conflict = 1; |
| + | } |
| } | |
| VDBG("state = %d, source ip conflict = %d, target ip conflict = %d\n", | |