emo/busybox
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

udhcpc: properly reduce timeout if bogus packets were received

Browse Source
This commit is contained in:
Denis Vlasenko 2008-05-21 07:02:16 +00:00
parent 54b90b5988
commit b23429198e
1 changed files with 16 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
networking/udhcp/dhcpc.c
View File

@ -343,8 +343,7 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv)
* "continue" statements in code below jump to the top of the loop. * "continue" statements in code below jump to the top of the loop.
*/ */
for (;;) { for (;;) {
tv.tv_sec = timeout; unsigned timestamp_before_wait;
tv.tv_usec = 0;
if (listen_mode != LISTEN_NONE && sockfd < 0) { if (listen_mode != LISTEN_NONE && sockfd < 0) {
if (listen_mode == LISTEN_KERNEL) if (listen_mode == LISTEN_KERNEL)
@ -354,19 +353,20 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv)
} }
max_fd = udhcp_sp_fd_set(&rfds, sockfd); max_fd = udhcp_sp_fd_set(&rfds, sockfd);
tv.tv_sec = timeout;
tv.tv_usec = 0;
retval = 0; /* If we already timed out, fall through, else... */ retval = 0; /* If we already timed out, fall through, else... */
if (tv.tv_sec > 0) { if (tv.tv_sec > 0) {
timestamp_before_wait = (unsigned)monotonic_sec();
DEBUG("Waiting on select..."); DEBUG("Waiting on select...");
retval = select(max_fd + 1, &rfds, NULL, NULL, &tv); retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
} if (retval < 0) {
/* EINTR? A signal was caught, don't panic */
if (retval < 0) { if (errno == EINTR)
/* EINTR? signal was caught, don't panic */ continue;
if (errno != EINTR) {
/* Else: an error occured, panic! */ /* Else: an error occured, panic! */
bb_perror_msg_and_die("select"); bb_perror_msg_and_die("select");
} }
continue;
} }
/* If timeout dropped to zero, time to become active: /* If timeout dropped to zero, time to become active:
@ -431,7 +431,7 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv)
/* send a request packet */ /* send a request packet */
send_renew(xid, server_addr, requested_ip); /* unicast */ send_renew(xid, server_addr, requested_ip); /* unicast */
t1 += (t2 - t1) / 2; t1 += (t2 - t1) / 2;
timeout = t1 - ((int)monotonic_sec() - timestamp_got_lease); timeout = t1 - ((unsigned)monotonic_sec() - timestamp_got_lease);
continue; continue;
} }
/* Timed out, enter rebinding state */ /* Timed out, enter rebinding state */
@ -446,7 +446,7 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv)
/* send a request packet */ /* send a request packet */
send_renew(xid, 0, requested_ip); /* broadcast */ send_renew(xid, 0, requested_ip); /* broadcast */
t2 += (lease_seconds - t2) / 2; t2 += (lease_seconds - t2) / 2;
timeout = t2 - ((int)monotonic_sec() - timestamp_got_lease); timeout = t2 - ((unsigned)monotonic_sec() - timestamp_got_lease);
continue; continue;
} }
/* Timed out, enter init state */ /* Timed out, enter init state */
@ -474,6 +474,11 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv)
else else
len = get_raw_packet(&packet, sockfd); len = get_raw_packet(&packet, sockfd);
/* If this packet will turn out to be unrelated/bogus,
* we will go back and wait for next one.
* Be sure timeout is properly decreased. */
timeout -= (unsigned)monotonic_sec() - timestamp_before_wait;
if (len == -1) { /* error is severe, reopen socket */ if (len == -1) { /* error is severe, reopen socket */
DEBUG("error on read, %s, reopening socket", strerror(errno)); DEBUG("error on read, %s, reopening socket", strerror(errno));
change_listen_mode(listen_mode); /* just close and reopen */ change_listen_mode(listen_mode); /* just close and reopen */
@ -628,7 +633,7 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv)
ret0: ret0:
retval = 0; retval = 0;
ret: ret:
/*if (client_config.pidfile) - remove_pidfile has it's own check */ /*if (client_config.pidfile) - remove_pidfile has its own check */
remove_pidfile(client_config.pidfile); remove_pidfile(client_config.pidfile);
return retval; return retval;
} }