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zcip: code shrink

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function                                             old     new   delta
zcip_main                                           1263    1230     -33

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2015-08-04 12:28:21 +02:00
parent 16aa7a73c4
commit 99e30be38b
1 changed files with 59 additions and 78 deletions
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113
networking/zcip.c
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@ -215,19 +215,17 @@ int zcip_main(int argc UNUSED_PARAM, char **argv)
const struct ether_addr null_addr; const struct ether_addr null_addr;
struct ifreq ifr; struct ifreq ifr;
uint32_t chosen_nip; uint32_t chosen_nip;
int timeout_ms; /* must be signed */ int timeout_ms; // must be signed
unsigned conflicts; unsigned conflicts;
unsigned nprobes; unsigned nsent;
unsigned nclaims;
int verbose; int verbose;
} L; } L;
#define null_addr (L.null_addr ) #define null_addr (L.null_addr )
#define chosen_nip (L.chosen_nip)
#define ifr (L.ifr ) #define ifr (L.ifr )
#define chosen_nip (L.chosen_nip)
#define timeout_ms (L.timeout_ms) #define timeout_ms (L.timeout_ms)
#define conflicts (L.conflicts ) #define conflicts (L.conflicts )
#define nprobes (L.nprobes ) #define nsent (L.nsent )
#define nclaims (L.nclaims )
#define verbose (L.verbose ) #define verbose (L.verbose )
memset(&L, 0, sizeof(L)); memset(&L, 0, sizeof(L));
@ -351,8 +349,7 @@ int zcip_main(int argc UNUSED_PARAM, char **argv)
struct pollfd fds[1]; struct pollfd fds[1];
unsigned deadline_us; unsigned deadline_us;
struct arp_packet p; struct arp_packet p;
int source_ip_conflict; int ip_conflict;
int target_ip_conflict;
fds[0].fd = sock_fd; fds[0].fd = sock_fd;
fds[0].events = POLLIN; fds[0].events = POLLIN;
@ -368,8 +365,8 @@ int zcip_main(int argc UNUSED_PARAM, char **argv)
// set deadline_us to the point in time when we timeout // set deadline_us to the point in time when we timeout
deadline_us = MONOTONIC_US() + timeout_ms * 1000; deadline_us = MONOTONIC_US() + timeout_ms * 1000;
VDBG("...wait %d %s nprobes=%u, nclaims=%u\n", VDBG("...wait %d %s nsent=%u\n",
timeout_ms, argv_intf, nprobes, nclaims); timeout_ms, argv_intf, nsent);
switch (safe_poll(fds, 1, timeout_ms)) { switch (safe_poll(fds, 1, timeout_ms)) {
@ -384,10 +381,10 @@ int zcip_main(int argc UNUSED_PARAM, char **argv)
case PROBE: case PROBE:
// timeouts in the PROBE state mean no conflicting ARP packets // timeouts in the PROBE state mean no conflicting ARP packets
// have been received, so we can progress through the states // have been received, so we can progress through the states
if (nprobes < PROBE_NUM) { if (nsent < PROBE_NUM) {
nprobes++; nsent++;
VDBG("probe/%u %s@%s\n", VDBG("probe/%u %s@%s\n",
nprobes, argv_intf, nip_to_a(chosen_nip)); nsent, argv_intf, nip_to_a(chosen_nip));
timeout_ms = PROBE_MIN * 1000; timeout_ms = PROBE_MIN * 1000;
timeout_ms += random_delay_ms(PROBE_MAX - PROBE_MIN); timeout_ms += random_delay_ms(PROBE_MAX - PROBE_MIN);
arp(/* ARPOP_REQUEST, */ arp(/* ARPOP_REQUEST, */
@ -395,25 +392,25 @@ int zcip_main(int argc UNUSED_PARAM, char **argv)
&null_addr, chosen_nip); &null_addr, chosen_nip);
break; break;
} }
// Switch to announce state. // Switch to announce state
nclaims = 0; nsent = 0;
state = ANNOUNCE; state = ANNOUNCE;
goto send_announce; goto send_announce;
case ANNOUNCE: case ANNOUNCE:
// timeouts in the ANNOUNCE state mean no conflicting ARP packets // timeouts in the ANNOUNCE state mean no conflicting ARP packets
// have been received, so we can progress through the states // have been received, so we can progress through the states
if (nclaims < ANNOUNCE_NUM) { if (nsent < ANNOUNCE_NUM) {
send_announce: send_announce:
nclaims++; nsent++;
VDBG("announce/%u %s@%s\n", VDBG("announce/%u %s@%s\n",
nclaims, argv_intf, nip_to_a(chosen_nip)); nsent, argv_intf, nip_to_a(chosen_nip));
timeout_ms = ANNOUNCE_INTERVAL * 1000; timeout_ms = ANNOUNCE_INTERVAL * 1000;
arp(/* ARPOP_REQUEST, */ arp(/* ARPOP_REQUEST, */
/* &G.eth_addr, */ chosen_nip, /* &G.eth_addr, */ chosen_nip,
&G.eth_addr, chosen_nip); &G.eth_addr, chosen_nip);
break; break;
} }
// Switch to monitor state. // Switch to monitor state
// FIXME update filters // FIXME update filters
run(argv, "config", chosen_nip); run(argv, "config", chosen_nip);
// NOTE: all other exit paths should deconfig... // NOTE: all other exit paths should deconfig...
@ -424,7 +421,7 @@ int zcip_main(int argc UNUSED_PARAM, char **argv)
state = MONITOR; state = MONITOR;
break; break;
case DEFEND: case DEFEND:
// Defend period ended with no ARP replies - we won. // Defend period ended with no ARP replies - we won
conflicts = 0; conflicts = 0;
timeout_ms = -1; timeout_ms = -1;
state = MONITOR; state = MONITOR;
@ -443,7 +440,7 @@ int zcip_main(int argc UNUSED_PARAM, char **argv)
diff = 0; diff = 0;
} }
VDBG("adjusting timeout\n"); VDBG("adjusting timeout\n");
timeout_ms = (diff / 1000) | 1; /* never 0 */ timeout_ms = (diff / 1000) | 1; // never 0
} }
if ((fds[0].revents & POLLIN) == 0) { if ((fds[0].revents & POLLIN) == 0) {
@ -452,7 +449,7 @@ int zcip_main(int argc UNUSED_PARAM, char **argv)
// this shouldn't necessarily exit. // this shouldn't necessarily exit.
bb_error_msg("iface %s is down", argv_intf); bb_error_msg("iface %s is down", argv_intf);
if (state >= MONITOR) { if (state >= MONITOR) {
/* only if we are in MONITOR or DEFEND */ // only if we are in MONITOR or DEFEND
run(argv, "deconfig", chosen_nip); run(argv, "deconfig", chosen_nip);
} }
return EXIT_FAILURE; return EXIT_FAILURE;
@ -478,81 +475,65 @@ int zcip_main(int argc UNUSED_PARAM, char **argv)
struct ether_addr *tha = (struct ether_addr *) p.arp.arp_tha; struct ether_addr *tha = (struct ether_addr *) p.arp.arp_tha;
struct in_addr *spa = (struct in_addr *) p.arp.arp_spa; struct in_addr *spa = (struct in_addr *) p.arp.arp_spa;
struct in_addr *tpa = (struct in_addr *) p.arp.arp_tpa; struct in_addr *tpa = (struct in_addr *) p.arp.arp_tpa;
VDBG("%s recv arp type=%d, op=%d,\n", VDBG("source=%s %s\n", ether_ntoa(sha), inet_ntoa(*spa));
argv_intf, ntohs(p.eth.ether_type), VDBG("target=%s %s\n", ether_ntoa(tha), inet_ntoa(*tpa));
ntohs(p.arp.arp_op));
VDBG("\tsource=%s %s\n",
ether_ntoa(sha),
inet_ntoa(*spa));
VDBG("\ttarget=%s %s\n",
ether_ntoa(tha),
inet_ntoa(*tpa));
} }
#endif #endif
source_ip_conflict = 0; ip_conflict = 0;
target_ip_conflict = 0;
if (memcmp(&p.arp.arp_sha, &G.eth_addr, ETH_ALEN) != 0) { if (memcmp(&p.arp.arp_sha, &G.eth_addr, ETH_ALEN) != 0) {
if (memcmp(p.arp.arp_spa, &chosen_nip, 4) == 0) { if (memcmp(p.arp.arp_spa, &chosen_nip, 4) == 0) {
/* A probe or reply with source_ip == chosen ip */ // A probe or reply with source_ip == chosen ip
source_ip_conflict = 1; ip_conflict = 1;
} }
if (p.arp.arp_op == htons(ARPOP_REQUEST) if (p.arp.arp_op == htons(ARPOP_REQUEST)
&& memcmp(p.arp.arp_spa, &const_int_0, 4) == 0 && memcmp(p.arp.arp_spa, &const_int_0, 4) == 0
&& memcmp(p.arp.arp_tpa, &chosen_nip, 4) == 0 && memcmp(p.arp.arp_tpa, &chosen_nip, 4) == 0
) { ) {
/* A probe with source_ip == 0.0.0.0, target_ip == chosen ip: // A probe with source_ip == 0.0.0.0, target_ip == chosen ip:
* another host trying to claim this ip! // another host trying to claim this ip!
*/ ip_conflict |= 2;
target_ip_conflict = 1;
} }
} }
VDBG("state:%d ip_conflict:%d\n", state, ip_conflict);
if (!ip_conflict)
break;
VDBG("state = %d, source ip conflict = %d, target ip conflict = %d\n", // Either src or target IP conflict exists
state, source_ip_conflict, target_ip_conflict); if (state <= ANNOUNCE) {
switch (state) { // PROBE or ANNOUNCE
case PROBE:
case ANNOUNCE:
// When probing or announcing, check for source IP conflicts
// and other hosts doing ARP probes (target IP conflicts).
if (source_ip_conflict || target_ip_conflict) {
conflicts++; conflicts++;
timeout_ms = PROBE_MIN * 1000 timeout_ms = PROBE_MIN * 1000
+ CONFLICT_MULTIPLIER * random_delay_ms(conflicts); + CONFLICT_MULTIPLIER * random_delay_ms(conflicts);
chosen_nip = pick_nip(); chosen_nip = pick_nip();
nprobes = 0; nsent = 0;
nclaims = 0;
state = PROBE; state = PROBE;
}
break; break;
case MONITOR: }
// If a conflict, we try to defend with a single ARP probe. // MONITOR or DEFEND: only src IP conflict is a problem
if (source_ip_conflict) { if (ip_conflict & 1) {
VDBG("monitor conflict -- defending\n"); if (state == MONITOR) {
// Src IP conflict, defend with a single ARP probe
VDBG("monitor conflict - defending\n");
timeout_ms = DEFEND_INTERVAL * 1000; timeout_ms = DEFEND_INTERVAL * 1000;
state = DEFEND; state = DEFEND;
arp(/* ARPOP_REQUEST, */ arp(/* ARPOP_REQUEST, */
/* &G.eth_addr, */ chosen_nip, /* &G.eth_addr, */ chosen_nip,
&G.eth_addr, chosen_nip); &G.eth_addr, chosen_nip);
}
break; break;
case DEFEND: }
// Well, we tried. Start over (on conflict). // state == DEFEND
if (source_ip_conflict) { // Another src IP conflict, start over
VDBG("defend conflict -- starting over\n"); VDBG("defend conflict - starting over\n");
run(argv, "deconfig", chosen_nip); run(argv, "deconfig", chosen_nip);
// restart the whole protocol // restart the whole protocol
timeout_ms = 0; timeout_ms = 0;
chosen_nip = pick_nip(); chosen_nip = pick_nip();
nprobes = 0; nsent = 0;
nclaims = 0;
state = PROBE; state = PROBE;
} }
break; break; // case 1 (packet arrived)
} // switch state } // switch (poll)
break; // case 1 (packets arriving)
} // switch poll
} // while (1) } // while (1)
#undef argv_intf #undef argv_intf
} }