b23429198
Denis Vlasenko
2008-05-21
Subject
udhcpc: properly reduce timeout if bogus packets were received
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Commit Diff GitHub →
networking/udhcp/dhcpc.c+16 -11
| @@ -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. | |
| */ | |
| for (;;) { | |
| - | tv.tv_sec = timeout; |
| - | tv.tv_usec = 0; |
| + | unsigned timestamp_before_wait; |
| if (listen_mode != LISTEN_NONE && sockfd < 0) { | |
| 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); | |
| + | tv.tv_sec = timeout; |
| + | tv.tv_usec = 0; |
| retval = 0; /* If we already timed out, fall through, else... */ | |
| if (tv.tv_sec > 0) { | |
| + | timestamp_before_wait = (unsigned)monotonic_sec(); |
| DEBUG("Waiting on select..."); | |
| retval = select(max_fd + 1, &rfds, NULL, NULL, &tv); | |
| - | } |
| - | |
| - | if (retval < 0) { |
| - | /* EINTR? signal was caught, don't panic */ |
| - | if (errno != EINTR) { |
| + | if (retval < 0) { |
| + | /* EINTR? A signal was caught, don't panic */ |
| + | if (errno == EINTR) |
| + | continue; |
| /* Else: an error occured, panic! */ | |
| bb_perror_msg_and_die("select"); | |
| } | |
| - | continue; |
| } | |
| /* 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_renew(xid, server_addr, requested_ip); /* unicast */ | |
| t1 += (t2 - t1) / 2; | |
| - | timeout = t1 - ((int)monotonic_sec() - timestamp_got_lease); |
| + | timeout = t1 - ((unsigned)monotonic_sec() - timestamp_got_lease); |
| continue; | |
| } | |
| /* Timed out, enter rebinding state */ | |
| @@ -446,7 +446,7 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv) | |
| /* send a request packet */ | |
| send_renew(xid, 0, requested_ip); /* broadcast */ | |
| t2 += (lease_seconds - t2) / 2; | |
| - | timeout = t2 - ((int)monotonic_sec() - timestamp_got_lease); |
| + | timeout = t2 - ((unsigned)monotonic_sec() - timestamp_got_lease); |
| continue; | |
| } | |
| /* Timed out, enter init state */ | |
| @@ -474,6 +474,11 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv) | |
| else | |
| 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 */ | |
| DEBUG("error on read, %s, reopening socket", strerror(errno)); | |
| change_listen_mode(listen_mode); /* just close and reopen */ | |
| @@ -628,7 +633,7 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv) | |
| ret0: | |
| retval = 0; | |
| 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); | |
| return retval; | |
| } | |