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Diffstat (limited to 'networking/zcip.c')
-rw-r--r--networking/zcip.c153
1 files changed, 87 insertions, 66 deletions
diff --git a/networking/zcip.c b/networking/zcip.c
index a16a642..129155f 100644
--- a/networking/zcip.c
+++ b/networking/zcip.c
@@ -39,7 +39,7 @@
#define MONOTONIC_US() ((unsigned)monotonic_us())
struct arp_packet {
- struct ether_header hdr;
+ struct ether_header eth;
struct ether_arp arp;
} ATTRIBUTE_PACKED;
@@ -69,8 +69,21 @@ enum {
DEFEND
};
-#define VDBG(fmt,args...) \
- do { } while (0)
+#define VDBG(...) do { } while (0)
+
+
+enum {
+ sock_fd = 3
+};
+
+struct globals {
+ char *intf;
+ struct sockaddr saddr;
+};
+#define G (*(struct globals*)&bb_common_bufsiz1)
+#define intf (G.intf )
+#define saddr (G.saddr)
+
/**
* Pick a random link local IP address on 169.254/16, except that
@@ -89,17 +102,17 @@ static void pick(struct in_addr *ip)
/**
* Broadcast an ARP packet.
*/
-static void arp(int fd, struct sockaddr *saddr, int op,
- const struct ether_addr *source_addr, struct in_addr source_ip,
- const struct ether_addr *target_addr, struct in_addr target_ip)
+static void arp(int op,
+ const struct ether_addr *source_eth, struct in_addr source_ip,
+ const struct ether_addr *target_eth, struct in_addr target_ip)
{
struct arp_packet p;
memset(&p, 0, sizeof(p));
// ether header
- p.hdr.ether_type = htons(ETHERTYPE_ARP);
- memcpy(p.hdr.ether_shost, source_addr, ETH_ALEN);
- memset(p.hdr.ether_dhost, 0xff, ETH_ALEN);
+ p.eth.ether_type = htons(ETHERTYPE_ARP);
+ memcpy(p.eth.ether_shost, source_eth, ETH_ALEN);
+ memset(p.eth.ether_dhost, 0xff, ETH_ALEN);
// arp request
p.arp.arp_hrd = htons(ARPHRD_ETHER);
@@ -107,13 +120,13 @@ static void arp(int fd, struct sockaddr *saddr, int op,
p.arp.arp_hln = ETH_ALEN;
p.arp.arp_pln = 4;
p.arp.arp_op = htons(op);
- memcpy(&p.arp.arp_sha, source_addr, ETH_ALEN);
+ memcpy(&p.arp.arp_sha, source_eth, ETH_ALEN);
memcpy(&p.arp.arp_spa, &source_ip, sizeof(p.arp.arp_spa));
- memcpy(&p.arp.arp_tha, target_addr, ETH_ALEN);
+ memcpy(&p.arp.arp_tha, target_eth, ETH_ALEN);
memcpy(&p.arp.arp_tpa, &target_ip, sizeof(p.arp.arp_tpa));
// send it
- xsendto(fd, &p, sizeof(p), saddr, sizeof(*saddr));
+ xsendto(sock_fd, &p, sizeof(p), &saddr, sizeof(saddr));
// Currently all callers ignore errors, that's why returns are
// commented out...
@@ -123,21 +136,24 @@ static void arp(int fd, struct sockaddr *saddr, int op,
/**
* Run a script. argv[2] is already NULL.
*/
-static int run(char *argv[3], const char *intf, struct in_addr *ip)
+static int run(char *argv[3], struct in_addr *ip)
{
int status;
+ char *addr = addr; /* for gcc */
+ const char *fmt = "%s %s %s" + 3;
VDBG("%s run %s %s\n", intf, argv[0], argv[1]);
if (ip) {
- char *addr = inet_ntoa(*ip);
+ addr = inet_ntoa(*ip);
setenv("ip", addr, 1);
- bb_info_msg("%s %s %s", argv[1], intf, addr);
+ fmt -= 3;
}
+ bb_info_msg(fmt, argv[1], intf, addr);
status = wait4pid(spawn(argv));
if (status < 0) {
- bb_perror_msg("%s %s", argv[1], intf);
+ bb_perror_msg("%s %s %s" + 3, argv[1], intf);
return -errno;
}
if (status != 0)
@@ -148,7 +164,7 @@ static int run(char *argv[3], const char *intf, struct in_addr *ip)
/**
* Return milliseconds of random delay, up to "secs" seconds.
*/
-static unsigned ALWAYS_INLINE ms_rdelay(unsigned secs)
+static unsigned ALWAYS_INLINE random_delay_ms(unsigned secs)
{
return rand() % (secs * 1000);
}
@@ -160,10 +176,8 @@ int zcip_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int zcip_main(int argc, char **argv)
{
int state = PROBE;
- /* Prevent unaligned traps for ARM (see srand() below) */
- struct ether_addr eth_addr __attribute__(( aligned(sizeof(unsigned)) ));
+ struct ether_addr eth_addr;
const char *why;
- int fd;
char *r_opt;
unsigned opts;
@@ -171,10 +185,8 @@ int zcip_main(int argc, char **argv)
struct {
const struct in_addr null_ip;
const struct ether_addr null_addr;
- struct sockaddr saddr;
struct in_addr ip;
struct ifreq ifr;
- char *intf;
char *script_av[3];
int timeout_ms; /* must be signed */
unsigned conflicts;
@@ -185,10 +197,8 @@ int zcip_main(int argc, char **argv)
} L;
#define null_ip (L.null_ip )
#define null_addr (L.null_addr )
-#define saddr (L.saddr )
#define ip (L.ip )
#define ifr (L.ifr )
-#define intf (L.intf )
#define script_av (L.script_av )
#define timeout_ms (L.timeout_ms)
#define conflicts (L.conflicts )
@@ -231,29 +241,37 @@ int zcip_main(int argc, char **argv)
// initialize the interface (modprobe, ifup, etc)
script_av[1] = (char*)"init";
- if (run(script_av, intf, NULL))
+ if (run(script_av, NULL))
return EXIT_FAILURE;
// initialize saddr
+ // saddr is: { u16 sa_family; u8 sa_data[14]; }
//memset(&saddr, 0, sizeof(saddr));
+ //TODO: are we leaving sa_family == 0 (AF_UNSPEC)?!
safe_strncpy(saddr.sa_data, intf, sizeof(saddr.sa_data));
// open an ARP socket
- fd = xsocket(PF_PACKET, SOCK_PACKET, htons(ETH_P_ARP));
+ xmove_fd(xsocket(AF_PACKET, SOCK_PACKET, htons(ETH_P_ARP)), sock_fd);
// bind to the interface's ARP socket
- xbind(fd, &saddr, sizeof(saddr));
+ xbind(sock_fd, &saddr, sizeof(saddr));
// get the interface's ethernet address
//memset(&ifr, 0, sizeof(ifr));
strncpy(ifr.ifr_name, intf, sizeof(ifr.ifr_name));
- xioctl(fd, SIOCGIFHWADDR, &ifr);
+ xioctl(sock_fd, SIOCGIFHWADDR, &ifr);
memcpy(&eth_addr, &ifr.ifr_hwaddr.sa_data, ETH_ALEN);
// start with some stable ip address, either a function of
// the hardware address or else the last address we used.
+ // we are taking low-order four bytes, as top-order ones
+ // aren't random enough.
// NOTE: the sequence of addresses we try changes only
// depending on when we detect conflicts.
- srand(*(unsigned*)&eth_addr);
+ {
+ uint32_t t;
+ memcpy(&t, (char*)&eth_addr + 2, 4);
+ srand(t);
+ }
if (ip.s_addr == 0)
pick(&ip);
@@ -281,18 +299,17 @@ int zcip_main(int argc, char **argv)
struct pollfd fds[1];
unsigned deadline_us;
struct arp_packet p;
+ int source_ip_conflict;
+ int target_ip_conflict;
- int source_ip_conflict = 0;
- int target_ip_conflict = 0;
-
- fds[0].fd = fd;
+ fds[0].fd = sock_fd;
fds[0].events = POLLIN;
fds[0].revents = 0;
// poll, being ready to adjust current timeout
if (!timeout_ms) {
- timeout_ms = ms_rdelay(PROBE_WAIT);
- // FIXME setsockopt(fd, SO_ATTACH_FILTER, ...) to
+ timeout_ms = random_delay_ms(PROBE_WAIT);
+ // FIXME setsockopt(sock_fd, SO_ATTACH_FILTER, ...) to
// make the kernel filter out all packets except
// ones we'd care about.
}
@@ -302,6 +319,8 @@ int zcip_main(int argc, char **argv)
VDBG("...wait %d %s nprobes=%u, nclaims=%u\n",
timeout_ms, intf, nprobes, nclaims);
+ // FIXME: do we really receive ALL packets here??
+ // if yes, set up filtering to get ARPs only!!! (see arping)
switch (safe_poll(fds, 1, timeout_ms)) {
default:
@@ -319,11 +338,11 @@ int zcip_main(int argc, char **argv)
nprobes++;
VDBG("probe/%u %s@%s\n",
nprobes, intf, inet_ntoa(ip));
- arp(fd, &saddr, ARPOP_REQUEST,
+ arp(ARPOP_REQUEST,
&eth_addr, null_ip,
&null_addr, ip);
timeout_ms = PROBE_MIN * 1000;
- timeout_ms += ms_rdelay(PROBE_MAX - PROBE_MIN);
+ timeout_ms += random_delay_ms(PROBE_MAX - PROBE_MIN);
}
else {
// Switch to announce state.
@@ -331,7 +350,7 @@ int zcip_main(int argc, char **argv)
nclaims = 0;
VDBG("announce/%u %s@%s\n",
nclaims, intf, inet_ntoa(ip));
- arp(fd, &saddr, ARPOP_REQUEST,
+ arp(ARPOP_REQUEST,
&eth_addr, ip,
&eth_addr, ip);
timeout_ms = ANNOUNCE_INTERVAL * 1000;
@@ -344,7 +363,7 @@ int zcip_main(int argc, char **argv)
nclaims = 0;
VDBG("announce/%u %s@%s\n",
nclaims, intf, inet_ntoa(ip));
- arp(fd, &saddr, ARPOP_REQUEST,
+ arp(ARPOP_REQUEST,
&eth_addr, ip,
&eth_addr, ip);
timeout_ms = ANNOUNCE_INTERVAL * 1000;
@@ -356,7 +375,7 @@ int zcip_main(int argc, char **argv)
nclaims++;
VDBG("announce/%u %s@%s\n",
nclaims, intf, inet_ntoa(ip));
- arp(fd, &saddr, ARPOP_REQUEST,
+ arp(ARPOP_REQUEST,
&eth_addr, ip,
&eth_addr, ip);
timeout_ms = ANNOUNCE_INTERVAL * 1000;
@@ -367,7 +386,7 @@ int zcip_main(int argc, char **argv)
// link is ok to use earlier
// FIXME update filters
script_av[1] = (char*)"config";
- run(script_av, intf, &ip);
+ run(script_av, &ip);
ready = 1;
conflicts = 0;
timeout_ms = -1; // Never timeout in the monitor state.
@@ -395,7 +414,7 @@ int zcip_main(int argc, char **argv)
} // switch (state)
break; // case 0 (timeout)
- // packets arriving
+ // packets arriving, or link went down
case 1:
// We need to adjust the timeout in case we didn't receive
// a conflicting packet.
@@ -408,8 +427,7 @@ int zcip_main(int argc, char **argv)
timeout_ms = 0;
} else {
VDBG("adjusting timeout\n");
- timeout_ms = diff / 1000;
- if (!timeout_ms) timeout_ms = 1;
+ timeout_ms = (diff / 1000) | 1; /* never 0 */
}
}
@@ -417,10 +435,10 @@ int zcip_main(int argc, char **argv)
if (fds[0].revents & POLLERR) {
// FIXME: links routinely go down;
// this shouldn't necessarily exit.
- bb_error_msg("%s: poll error", intf);
+ bb_error_msg("iface %s is down", intf);
if (ready) {
script_av[1] = (char*)"deconfig";
- run(script_av, intf, &ip);
+ run(script_av, &ip);
}
return EXIT_FAILURE;
}
@@ -428,21 +446,20 @@ int zcip_main(int argc, char **argv)
}
// read ARP packet
- if (recv(fd, &p, sizeof(p), 0) < 0) {
+ if (safe_read(sock_fd, &p, sizeof(p)) < 0) {
why = "recv";
goto bad;
}
- if (p.hdr.ether_type != htons(ETHERTYPE_ARP))
+ if (p.eth.ether_type != htons(ETHERTYPE_ARP))
continue;
-
#ifdef DEBUG
{
- struct ether_addr * sha = (struct ether_addr *) p.arp.arp_sha;
- 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;
+ struct ether_addr *sha = (struct ether_addr *) p.arp.arp_sha;
+ 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",
- intf, ntohs(p.hdr.ether_type),
+ intf, ntohs(p.eth.ether_type),
ntohs(p.arp.arp_op));
VDBG("\tsource=%s %s\n",
ether_ntoa(sha),
@@ -453,16 +470,21 @@ int zcip_main(int argc, 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;
- if (memcmp(p.arp.arp_spa, &ip.s_addr, sizeof(struct in_addr)) == 0 &&
- memcmp(&eth_addr, &p.arp.arp_sha, ETH_ALEN) != 0) {
+ 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, &eth_addr, ETH_ALEN) != 0
+ ) {
source_ip_conflict = 1;
}
- if (memcmp(p.arp.arp_tpa, &ip.s_addr, sizeof(struct in_addr)) == 0 &&
- p.arp.arp_op == htons(ARPOP_REQUEST) &&
- memcmp(&eth_addr, &p.arp.arp_tha, ETH_ALEN) != 0) {
+ 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, &eth_addr, ETH_ALEN) != 0
+ ) {
target_ip_conflict = 1;
}
@@ -494,10 +516,9 @@ int zcip_main(int argc, char **argv)
VDBG("monitor conflict -- defending\n");
state = DEFEND;
timeout_ms = DEFEND_INTERVAL * 1000;
- arp(fd, &saddr,
- ARPOP_REQUEST,
- &eth_addr, ip,
- &eth_addr, ip);
+ arp(ARPOP_REQUEST,
+ &eth_addr, ip,
+ &eth_addr, ip);
}
break;
case DEFEND:
@@ -507,7 +528,7 @@ int zcip_main(int argc, char **argv)
VDBG("defend conflict -- starting over\n");
ready = 0;
script_av[1] = (char*)"deconfig";
- run(script_av, intf, &ip);
+ run(script_av, &ip);
// restart the whole protocol
pick(&ip);
@@ -530,6 +551,6 @@ int zcip_main(int argc, char **argv)
} // switch poll
} // while (1)
bad:
- bb_perror_msg("%s, %s", intf, why);
+ bb_perror_msg("%s: %s", intf, why);
return EXIT_FAILURE;
}
generated by cgit v1.1 at 2024-12-26 19:41:36 +0000