docs/logging_and_backgrounding.txt: new mini-doc
[oweals/busybox.git] / networking / udhcp / dhcpc.c
index d135ba74db24b4b6de072f582e74f00e1408bc45..e9f99e39c83e8d18573638cab3f2ec06e70b9831 100644 (file)
@@ -43,11 +43,17 @@ static void change_listen_mode(int new_mode)
 {
        DEBUG("entering %s listen mode",
                new_mode ? (new_mode == 1 ? "kernel" : "raw") : "none");
+
+       listen_mode = new_mode;
        if (sockfd >= 0) {
                close(sockfd);
                sockfd = -1;
        }
-       listen_mode = new_mode;
+       if (new_mode == LISTEN_KERNEL)
+               sockfd = udhcp_listen_socket(/*INADDR_ANY,*/ CLIENT_PORT, client_config.interface);
+       else if (new_mode != LISTEN_NONE)
+               sockfd = udhcp_raw_socket(client_config.ifindex);
+       /* else LISTEN_NONE: sockfd stay closed */
 }
 
 
@@ -123,7 +129,7 @@ static uint8_t* alloc_dhcp_option(int code, const char *str, int extra)
 
 
 int udhcpc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv)
+int udhcpc_main(int argc UNUSED_PARAM, char **argv)
 {
        uint8_t *temp, *message;
        char *str_c, *str_V, *str_h, *str_F, *str_r;
@@ -169,12 +175,8 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv)
                "no-default-options\0" No_argument   "o"
                "foreground\0"     No_argument       "f"
                "background\0"     No_argument       "b"
-#if ENABLE_FEATURE_UDHCPC_ARPING
-               "arping\0"         No_argument       "a"
-#endif
-#if ENABLE_FEATURE_UDHCP_PORT
-               "client-port\0"    Required_argument "P"
-#endif
+               USE_FEATURE_UDHCPC_ARPING("arping\0"    No_argument       "a")
+               USE_FEATURE_UDHCP_PORT("client-port\0"  Required_argument "P")
                ;
 #endif
        enum {
@@ -184,8 +186,8 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv)
                OPT_H = 1 << 3,
                OPT_h = 1 << 4,
                OPT_F = 1 << 5,
-               OPT_i = 1 << 6, 
-               OPT_n = 1 << 7, 
+               OPT_i = 1 << 6,
+               OPT_n = 1 << 7,
                OPT_p = 1 << 8,
                OPT_q = 1 << 9,
                OPT_R = 1 << 10,
@@ -201,40 +203,24 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv)
                OPT_f = 1 << 20,
 /* The rest has variable bit positions, need to be clever */
                OPTBIT_f = 20,
-#if BB_MMU
-               OPTBIT_b,
-#endif
-#if ENABLE_FEATURE_UDHCPC_ARPING
-               OPTBIT_a,
-#endif
-#if ENABLE_FEATURE_UDHCP_PORT
-               OPTBIT_P,
-#endif
-#if BB_MMU
-               OPT_b = 1 << OPTBIT_b,
-#endif
-#if ENABLE_FEATURE_UDHCPC_ARPING
-               OPT_a = 1 << OPTBIT_a,
-#endif
-#if ENABLE_FEATURE_UDHCP_PORT
-               OPT_P = 1 << OPTBIT_P,
-#endif
+               USE_FOR_MMU(              OPTBIT_b,)
+               USE_FEATURE_UDHCPC_ARPING(OPTBIT_a,)
+               USE_FEATURE_UDHCP_PORT(   OPTBIT_P,)
+               USE_FOR_MMU(              OPT_b = 1 << OPTBIT_b,)
+               USE_FEATURE_UDHCPC_ARPING(OPT_a = 1 << OPTBIT_a,)
+               USE_FEATURE_UDHCP_PORT(   OPT_P = 1 << OPTBIT_P,)
        };
 
        /* Default options. */
-#if ENABLE_FEATURE_UDHCP_PORT
-       SERVER_PORT = 67;
-       CLIENT_PORT = 68;
-#endif
+       USE_FEATURE_UDHCP_PORT(SERVER_PORT = 67;)
+       USE_FEATURE_UDHCP_PORT(CLIENT_PORT = 68;)
        client_config.interface = "eth0";
        client_config.script = DEFAULT_SCRIPT;
 
        /* Parse command line */
        /* Cc: mutually exclusive; O: list; -T,-t,-A take numeric param */
        opt_complementary = "c--C:C--c:O::T+:t+:A+";
-#if ENABLE_GETOPT_LONG
-       applet_long_options = udhcpc_longopts;
-#endif
+       USE_GETOPT_LONG(applet_long_options = udhcpc_longopts;)
        opt = getopt32(argv, "c:CV:H:h:F:i:np:qRr:s:T:t:vSA:O:of"
                USE_FOR_MMU("b")
                USE_FEATURE_UDHCPC_ARPING("a")
@@ -257,7 +243,7 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv)
                /* Flags: 0000NEOS
                S: 1 => Client requests Server to update A RR in DNS as well as PTR
                O: 1 => Server indicates to client that DNS has been updated regardless
-               E: 1 => Name data is DNS format, i.e. <4>host<6>domain<4>com<0> not "host.domain.com"
+               E: 1 => Name data is DNS format, i.e. <4>host<6>domain<3>com<0> not "host.domain.com"
                N: 1 => Client requests Server to not update DNS
                */
                client_config.fqdn[OPT_DATA + 0] = 0x1;
@@ -279,26 +265,26 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv)
        if (opt & OPT_o)
                client_config.no_default_options = 1;
        while (list_O) {
-               int n = index_in_strings(dhcp_option_strings, list_O->data);
+               char *optstr = llist_pop(&list_O);
+               int n = index_in_strings(dhcp_option_strings, optstr);
                if (n < 0)
-                       bb_error_msg_and_die("unknown option '%s'", list_O->data);
+                       bb_error_msg_and_die("unknown option '%s'", optstr);
                n = dhcp_options[n].code;
                client_config.opt_mask[n >> 3] |= 1 << (n & 7);
-               list_O = list_O->link;
        }
 
-       if (read_interface(client_config.interface, &client_config.ifindex,
+       if (udhcp_read_interface(client_config.interface, &client_config.ifindex,
                           NULL, client_config.arp))
                return 1;
 #if !BB_MMU
        /* on NOMMU reexec (i.e., background) early */
        if (!(opt & OPT_f)) {
                bb_daemonize_or_rexec(0 /* flags */, argv);
-               logmode = 0;
+               logmode = LOGMODE_NONE;
        }
 #endif
        if (opt & OPT_S) {
-               openlog(applet_name, LOG_PID, LOG_LOCAL0);
+               openlog(applet_name, LOG_PID, LOG_DAEMON);
                logmode |= LOGMODE_SYSLOG;
        }
 
@@ -338,14 +324,18 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv)
         * "continue" statements in code below jump to the top of the loop.
         */
        for (;;) {
-               unsigned timestamp_before_wait;
+               /* silence "uninitialized!" warning */
+               unsigned timestamp_before_wait = timestamp_before_wait;
+
+               //bb_error_msg("sockfd:%d, listen_mode:%d", sockfd, listen_mode);
+
+               /* Was opening raw or udp socket here
+                * if (listen_mode != LISTEN_NONE && sockfd < 0),
+                * but on fast network renew responses return faster
+                * than we open sockets. Thus this code is moved
+                * to change_listen_mode(). Thus we open listen socket
+                * BEFORE we send renew request (see "case BOUND:"). */
 
-               if (listen_mode != LISTEN_NONE && sockfd < 0) {
-                       if (listen_mode == LISTEN_KERNEL)
-                               sockfd = listen_socket(/*INADDR_ANY,*/ CLIENT_PORT, client_config.interface);
-                       else
-                               sockfd = raw_socket(client_config.ifindex);
-               }
                max_fd = udhcp_sp_fd_set(&rfds, sockfd);
 
                tv.tv_sec = timeout - already_waited_sec;
@@ -368,7 +358,7 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv)
                 * resend discover/renew/whatever
                 */
                if (retval == 0) {
-                       /* We will restart wait afresh in any case */
+                       /* We will restart the wait in any case */
                        already_waited_sec = 0;
 
                        switch (state) {
@@ -383,6 +373,7 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv)
                                        packet_num++;
                                        continue;
                                }
+ leasefail:
                                udhcp_run_script(NULL, "leasefail");
 #if BB_MMU /* -b is not supported on NOMMU */
                                if (opt & OPT_b) { /* background if no lease */
@@ -408,7 +399,7 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv)
                                        if (state == RENEW_REQUESTED) /* unicast */
                                                send_renew(xid, server_addr, requested_ip);
                                        else /* broadcast */
-                                               send_selecting(xid, server_addr, requested_ip);
+                                               send_select(xid, server_addr, requested_ip);
 
                                        timeout = discover_timeout;
                                        packet_num++;
@@ -418,6 +409,13 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv)
                                if (state == RENEW_REQUESTED)
                                        udhcp_run_script(NULL, "deconfig");
                                change_listen_mode(LISTEN_RAW);
+                               /* "discover...select...discover..." loops
+                                * were seen in the wild. Treat them similarly
+                                * to "no response to discover" case */
+                               if (state == REQUESTING) {
+                                       state = INIT_SELECTING;
+                                       goto leasefail;
+                               }
                                state = INIT_SELECTING;
                                timeout = 0;
                                packet_num = 0;
@@ -444,7 +442,7 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv)
                                 * try to find DHCP server using broadcast */
                                if (timeout > 0) {
                                        /* send a request packet */
-                                       send_renew(xid, 0, requested_ip); /* broadcast */
+                                       send_renew(xid, 0 /*INADDR_ANY*/, requested_ip); /* broadcast */
                                        timeout >>= 1;
                                        continue;
                                }
@@ -464,7 +462,7 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv)
                }
 
                /* select() didn't timeout, something did happen. */
-               /* Is is a packet? */
+               /* Is it a packet? */
                if (listen_mode != LISTEN_NONE && FD_ISSET(sockfd, &rfds)) {
                        int len;
                        /* A packet is ready, read it */
@@ -486,7 +484,7 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv)
                                continue;
 
                        if (packet.xid != xid) {
-                               DEBUG("Ignoring XID %x (our xid is %x)",
+                               DEBUG("Ignoring xid %x (our xid is %x)",
                                        (unsigned)packet.xid, (unsigned)xid);
                                continue;
                        }
@@ -515,7 +513,7 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv)
                                                /* still selecting - this server looks bad */
                                        }
                                        /* it IS unaligned sometimes, don't "optimize" */
-                                       server_addr = get_unaligned_u32p((uint32_t*)temp);
+                                       move_from_unaligned32(server_addr, temp);
                                        xid = packet.xid;
                                        requested_ip = packet.yiaddr;
 
@@ -536,8 +534,8 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv)
                                                bb_error_msg("no lease time with ACK, using 1 hour lease");
                                                lease_seconds = 60 * 60;
                                        } else {
-                                               /* can be misaligned, thus memcpy */
-                                               memcpy(&lease_seconds, temp, 4);
+                                               /* it IS unaligned sometimes, don't "optimize" */
+                                               move_from_unaligned32(lease_seconds, temp);
                                                lease_seconds = ntohl(lease_seconds);
                                                lease_seconds &= 0x0fffffff; /* paranoia: must not be prone to overflows */
                                                if (lease_seconds < 10) /* and not too small */
@@ -545,6 +543,15 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv)
                                        }
 #if ENABLE_FEATURE_UDHCPC_ARPING
                                        if (opt & OPT_a) {
+/* RFC 2131 3.1 paragraph 5:
+ * "The client receives the DHCPACK message with configuration
+ * parameters. The client SHOULD perform a final check on the
+ * parameters (e.g., ARP for allocated network address), and notes
+ * the duration of the lease specified in the DHCPACK message. At this
+ * point, the client is configured. If the client detects that the
+ * address is already in use (e.g., through the use of ARP),
+ * the client MUST send a DHCPDECLINE message to the server and restarts
+ * the configuration process..." */
                                                if (!arpping(packet.yiaddr,
                                                            (uint32_t) 0,
                                                            client_config.arp,
@@ -576,7 +583,7 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv)
                                        }
                                        requested_ip = packet.yiaddr;
                                        udhcp_run_script(&packet,
-                                                  ((state == RENEWING || state == REBINDING) ? "renew" : "bound"));
+                                                       ((state == RENEWING || state == REBINDING) ? "renew" : "bound"));
 
                                        state = BOUND;
                                        change_listen_mode(LISTEN_NONE);