zcip: code shrink

function                                             old     new   delta
zcip_main                                           1263    1230     -33

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 59 insertions, 78 deletions

diff --git a/networking/zcip.c b/networking/zcip.c
index 69644b230..5877a8317 100644
--- a/networking/zcip.c
+++ b/networking/zcip.c
@@ -215,19 +215,17 @@ int zcip_main(int argc UNUSED_PARAM, char **argv)
                 const struct ether_addr null_addr;
                 struct ifreq ifr;
                 uint32_t chosen_nip;
-                int timeout_ms; /* must be signed */
+                int timeout_ms; // must be signed
                 unsigned conflicts;
-                unsigned nprobes;
-                unsigned nclaims;
+                unsigned nsent;
                 int verbose;
         } L;
 #define null_addr  (L.null_addr )
-#define chosen_nip (L.chosen_nip)
 #define ifr        (L.ifr       )
+#define chosen_nip (L.chosen_nip)
 #define timeout_ms (L.timeout_ms)
 #define conflicts  (L.conflicts )
-#define nprobes    (L.nprobes   )
-#define nclaims    (L.nclaims   )
+#define nsent      (L.nsent     )
 #define verbose    (L.verbose   )
 
         memset(&L, 0, sizeof(L));
@@ -351,8 +349,7 @@ int zcip_main(int argc UNUSED_PARAM, char **argv)
                 struct pollfd fds[1];
                 unsigned deadline_us;
                 struct arp_packet p;
-                int source_ip_conflict;
-                int target_ip_conflict;
+                int ip_conflict;
 
                 fds[0].fd = sock_fd;
                 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
                 deadline_us = MONOTONIC_US() + timeout_ms * 1000;
 
-                VDBG("...wait %d %s nprobes=%u, nclaims=%u\n",
-                                timeout_ms, argv_intf, nprobes, nclaims);
+                VDBG("...wait %d %s nsent=%u\n",
+                                timeout_ms, argv_intf, nsent);
 
                 switch (safe_poll(fds, 1, timeout_ms)) {
 
@@ -384,10 +381,10 @@ int zcip_main(int argc UNUSED_PARAM, char **argv)
                         case PROBE:
                                 // timeouts in the PROBE state mean no conflicting ARP packets
                                 // have been received, so we can progress through the states
-                                if (nprobes < PROBE_NUM) {
-                                        nprobes++;
+                                if (nsent < PROBE_NUM) {
+                                        nsent++;
                                         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 += random_delay_ms(PROBE_MAX - PROBE_MIN);
                                         arp(/* ARPOP_REQUEST, */
@@ -395,25 +392,25 @@ int zcip_main(int argc UNUSED_PARAM, char **argv)
                                                         &null_addr, chosen_nip);
                                         break;
                                 }
-                                // Switch to announce state.
-                                nclaims = 0;
+                                // Switch to announce state
+                                nsent = 0;
                                 state = ANNOUNCE;
                                 goto send_announce;
                         case ANNOUNCE:
                                 // timeouts in the ANNOUNCE state mean no conflicting ARP packets
                                 // have been received, so we can progress through the states
-                                if (nclaims < ANNOUNCE_NUM) {
+                                if (nsent < ANNOUNCE_NUM) {
  send_announce:
-                                        nclaims++;
+                                        nsent++;
                                         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;
                                         arp(/* ARPOP_REQUEST, */
                                                         /* &G.eth_addr, */ chosen_nip,
                                                         &G.eth_addr, chosen_nip);
                                         break;
                                 }
-                                // Switch to monitor state.
+                                // Switch to monitor state
                                 // FIXME update filters
                                 run(argv, "config", chosen_nip);
                                 // NOTE: all other exit paths should deconfig...
@@ -424,7 +421,7 @@ int zcip_main(int argc UNUSED_PARAM, char **argv)
                                 state = MONITOR;
                                 break;
                         case DEFEND:
-                                // Defend period ended with no ARP replies - we won.
+                                // Defend period ended with no ARP replies - we won
                                 conflicts = 0;
                                 timeout_ms = -1;
                                 state = MONITOR;
@@ -443,7 +440,7 @@ int zcip_main(int argc UNUSED_PARAM, char **argv)
                                         diff = 0;
                                 }
                                 VDBG("adjusting timeout\n");
-                                timeout_ms = (diff / 1000) | 1; /* never 0 */
+                                timeout_ms = (diff / 1000) | 1; // never 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.
                                         bb_error_msg("iface %s is down", argv_intf);
                                         if (state >= MONITOR) {
-                                                /* only if we are in MONITOR or DEFEND */
+                                                // only if we are in MONITOR or DEFEND
                                                 run(argv, "deconfig", chosen_nip);
                                         }
                                         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 in_addr *spa = (struct in_addr *) p.arp.arp_spa;
                                 struct in_addr *tpa = (struct in_addr *) p.arp.arp_tpa;
-                                VDBG("%s recv arp type=%d, op=%d,\n",
-                                        argv_intf, ntohs(p.eth.ether_type),
-                                        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));
+                                VDBG("source=%s %s\n", ether_ntoa(sha), inet_ntoa(*spa));
+                                VDBG("target=%s %s\n", ether_ntoa(tha), inet_ntoa(*tpa));
                         }
 #endif
-                        source_ip_conflict = 0;
-                        target_ip_conflict = 0;
-
+                        ip_conflict = 0;
                         if (memcmp(&p.arp.arp_sha, &G.eth_addr, ETH_ALEN) != 0) {
                                 if (memcmp(p.arp.arp_spa, &chosen_nip, 4) == 0) {
-                                        /* A probe or reply with source_ip == chosen ip */
-                                        source_ip_conflict = 1;
+                                        // A probe or reply with source_ip == chosen ip
+                                        ip_conflict = 1;
                                 }
                                 if (p.arp.arp_op == htons(ARPOP_REQUEST)
                                  && memcmp(p.arp.arp_spa, &const_int_0, 4) == 0
                                  && memcmp(p.arp.arp_tpa, &chosen_nip, 4) == 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;
+                                        // A probe with source_ip == 0.0.0.0, target_ip == chosen ip:
+                                        // another host trying to claim this ip!
+                                        ip_conflict |= 2;
                                 }
                         }
+                        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",
-                                state, source_ip_conflict, target_ip_conflict);
-                        switch (state) {
-                        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++;
-                                        timeout_ms = PROBE_MIN * 1000
-                                                + CONFLICT_MULTIPLIER * random_delay_ms(conflicts);
-                                        chosen_nip = pick_nip();
-                                        nprobes = 0;
-                                        nclaims = 0;
-                                        state = PROBE;
-                                }
+                        // Either src or target IP conflict exists
+                        if (state <= ANNOUNCE) {
+                                // PROBE or ANNOUNCE
+                                conflicts++;
+                                timeout_ms = PROBE_MIN * 1000
+                                        + CONFLICT_MULTIPLIER * random_delay_ms(conflicts);
+                                chosen_nip = pick_nip();
+                                nsent = 0;
+                                state = PROBE;
                                 break;
-                        case MONITOR:
-                                // If a conflict, we try to defend with a single ARP probe.
-                                if (source_ip_conflict) {
-                                        VDBG("monitor conflict -- defending\n");
+                        }
+                        // MONITOR or DEFEND: only src IP conflict is a problem
+                        if (ip_conflict & 1) {
+                                if (state == MONITOR) {
+                                        // Src IP conflict, defend with a single ARP probe
+                                        VDBG("monitor conflict - defending\n");
                                         timeout_ms = DEFEND_INTERVAL * 1000;
                                         state = DEFEND;
                                         arp(/* ARPOP_REQUEST, */
                                                 /* &G.eth_addr, */ chosen_nip,
                                                 &G.eth_addr, chosen_nip);
+                                        break;
                                 }
-                                break;
-                        case DEFEND:
-                                // Well, we tried.  Start over (on conflict).
-                                if (source_ip_conflict) {
-                                        VDBG("defend conflict -- starting over\n");
-                                        run(argv, "deconfig", chosen_nip);
-
-                                        // restart the whole protocol
-                                        timeout_ms = 0;
-                                        chosen_nip = pick_nip();
-                                        nprobes = 0;
-                                        nclaims = 0;
-                                        state = PROBE;
-                                }
-                                break;
-                        } // switch state
-                        break; // case 1 (packets arriving)
-                } // switch poll
+                                // state == DEFEND
+                                // Another src IP conflict, start over
+                                VDBG("defend conflict - starting over\n");
+                                run(argv, "deconfig", chosen_nip);
+
+                                // restart the whole protocol
+                                timeout_ms = 0;
+                                chosen_nip = pick_nip();
+                                nsent = 0;
+                                state = PROBE;
+                        }
+                        break; // case 1 (packet arrived)
+                } // switch (poll)
         } // while (1)
 #undef argv_intf
 }