Merge branch 'busybox' into merge

8 files changed, 112 insertions, 52 deletions

diff --git a/networking/ftpgetput.c b/networking/ftpgetput.c
index f1d5ca571..ef0973a84 100644
--- a/networking/ftpgetput.c
+++ b/networking/ftpgetput.c
@@ -296,8 +296,7 @@ static const char ftpgetput_longopts[] ALIGN1 =
 int ftpgetput_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int ftpgetput_main(int argc UNUSED_PARAM, char **argv)
 {
-        const char *port = "ftp";
-        /* socket to ftp server */
+        const char *port = NULL;
 
 #if ENABLE_FTPPUT && !ENABLE_FTPGET
 # define ftp_action ftp_send
diff --git a/networking/httpd.c b/networking/httpd.c
index fcd1627b1..71e3a723f 100644
--- a/networking/httpd.c
+++ b/networking/httpd.c
@@ -102,6 +102,12 @@
 //config:       help
 //config:       HTTP server.
 //config:
+//config:config FEATURE_HTTPD_PORT_DEFAULT
+//config:       int "Default port"
+//config:       default 80
+//config:       range 1 65535
+//config:       depends on HTTPD
+//config:
 //config:config FEATURE_HTTPD_RANGES
 //config:       bool "Support 'Ranges:' header"
 //config:       default y
@@ -277,7 +283,7 @@
 //usage:        )
 //usage:     "\n        -f              Don't daemonize"
 //usage:     "\n        -v[v]           Verbose"
-//usage:     "\n        -p [IP:]PORT    Bind to IP:PORT (default *:80)"
+//usage:     "\n        -p [IP:]PORT    Bind to IP:PORT (default *:"STR(CONFIG_FEATURE_HTTPD_PORT_DEFAULT)")"
 //usage:        IF_FEATURE_HTTPD_SETUID(
 //usage:     "\n        -u USER[:GRP]   Set uid/gid after binding to port")
 //usage:        IF_FEATURE_HTTPD_BASIC_AUTH(
@@ -325,6 +331,9 @@
 
 static void send_REQUEST_TIMEOUT_and_exit(int sig) NORETURN;
 
+#define STR1(s) #s
+#define STR(s) STR1(s)
+
 static const char DEFAULT_PATH_HTTPD_CONF[] ALIGN1 = "/etc";
 static const char HTTPD_CONF[] ALIGN1 = "httpd.conf";
 static const char HTTP_200[] ALIGN1 = "HTTP/1.1 200 OK\r\n";
@@ -551,7 +560,7 @@ enum {
         SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
         IF_FEATURE_HTTPD_BASIC_AUTH(g_realm = "Web Server Authentication";) \
         IF_FEATURE_HTTPD_RANGES(range_start = -1;) \
-        bind_addr_or_port = "80"; \
+        bind_addr_or_port = STR(CONFIG_FEATURE_HTTPD_PORT_DEFAULT); \
         index_page = index_html; \
         file_size = -1; \
 } while (0)
diff --git a/networking/nc.c b/networking/nc.c
index 3483edb01..5525e41f9 100644
--- a/networking/nc.c
+++ b/networking/nc.c
@@ -226,7 +226,7 @@ int nc_main(int argc, char **argv)
                                 close(sfd);
                 } else {
                         cfd = create_and_connect_stream_or_die(argv[0],
-                                argv[1] ? bb_lookup_port(argv[1], "tcp", 0) : 0);
+                                bb_lookup_port(argv[1], "tcp", 0));
                 }
         }
 
diff --git a/networking/nc_bloaty.c b/networking/nc_bloaty.c
index 25b95246f..cfa133eae 100644
--- a/networking/nc_bloaty.c
+++ b/networking/nc_bloaty.c
@@ -813,8 +813,6 @@ int nc_main(int argc UNUSED_PARAM, char **argv)
         //if (option_mask32 & OPT_o) /* hexdump log */
         if (option_mask32 & OPT_p) { /* local source port */
                 o_lport = bb_lookup_port(str_p, o_udpmode ? "udp" : "tcp", 0);
-                if (!o_lport)
-                        bb_error_msg_and_die("bad local port '%s'", str_p);
         }
         //if (option_mask32 & OPT_r) /* randomize various things */
         //if (option_mask32 & OPT_u) /* use UDP */
@@ -827,9 +825,8 @@ int nc_main(int argc UNUSED_PARAM, char **argv)
 
         if (argv[0]) {
                 themaddr = xhost2sockaddr(argv[0],
-                        argv[1]
-                        ? bb_lookup_port(argv[1], o_udpmode ? "udp" : "tcp", 0)
-                        : 0);
+                        bb_lookup_port(argv[1], o_udpmode ? "udp" : "tcp", 0)
+                );
         }
 
         /* create & bind network socket */
diff --git a/networking/telnetd.c b/networking/telnetd.c
index de4d733f9..581da1924 100644
--- a/networking/telnetd.c
+++ b/networking/telnetd.c
@@ -68,6 +68,12 @@
 //config:       help
 //config:       Selecting this will make telnetd able to run standalone.
 //config:
+//config:config FEATURE_TELNETD_PORT_DEFAULT
+//config:       int "Default port"
+//config:       default 23
+//config:       range 1 65535
+//config:       depends on FEATURE_TELNETD_STANDALONE
+//config:
 //config:config FEATURE_TELNETD_INETD_WAIT
 //config:       bool "Support -w SEC option (inetd wait mode)"
 //config:       default y
@@ -103,7 +109,7 @@
 //usage:     "\n        -K              Close connection as soon as login exits"
 //usage:     "\n                        (normally wait until all programs close slave pty)"
 //usage:        IF_FEATURE_TELNETD_STANDALONE(
-//usage:     "\n        -p PORT         Port to listen on"
+//usage:     "\n        -p PORT         Port to listen on. Default "STR(CONFIG_FEATURE_TELNETD_PORT_DEFAULT)
 //usage:     "\n        -b ADDR[:PORT]  Address to bind to"
 //usage:     "\n        -F              Run in foreground"
 //usage:     "\n        -i              Inetd mode"
@@ -708,7 +714,7 @@ int telnetd_main(int argc UNUSED_PARAM, char **argv)
         } else {
                 master_fd = 0;
                 if (!(opt & OPT_WAIT)) {
-                        unsigned portnbr = 23;
+                        unsigned portnbr = CONFIG_FEATURE_TELNETD_PORT_DEFAULT;
                         if (opt & OPT_PORT)
                                 portnbr = xatou16(opt_portnbr);
                         master_fd = create_and_bind_stream_or_die(opt_bindaddr, portnbr);
diff --git a/networking/udhcp/common.h b/networking/udhcp/common.h
index ca778dab8..e374771cb 100644
--- a/networking/udhcp/common.h
+++ b/networking/udhcp/common.h
@@ -38,13 +38,27 @@ struct dhcp_packet {
 #define BROADCAST_FLAG 0x8000 /* "I need broadcast replies" */
         uint32_t ciaddr; /* client IP (if client is in BOUND, RENEW or REBINDING state) */
         uint32_t yiaddr; /* 'your' (client) IP address */
-        /* IP address of next server to use in bootstrap, returned in DHCPOFFER, DHCPACK by server */
+        /* IP address of "next server" (usually meant to be an TFTP server)
+         * to use in bootstrap, returned in DHCPOFFER, DHCPACK by server: */
         uint32_t siaddr_nip;
-        uint32_t gateway_nip; /* aka 'giaddr': relay agent IP address */
+        /* RFC 951 (BOOTP): "place my (server) IP address in the 'siaddr' field"
+         * (IOW: unconditionally, not just if we are also a TFTP server).
+         * DHCP servers don't have to do this, they add SERVER_ID option
+         * to their reply packets to let client identify lease-giving server.
+         */
+        uint32_t gateway_nip; /* aka 'giaddr': relay agent IP address, else 0 */
         uint8_t chaddr[16];   /* link-layer client hardware address (MAC) */
         uint8_t sname[64];    /* server host name (ASCIZ) */
+        /* RFC 951 (BOOTP): "If the client wishes to restrict booting
+         * to a particular server name, it may place [it] in 'sname'"
+         */
         uint8_t file[128];    /* boot file name (ASCIZ) */
-        uint32_t cookie;      /* fixed first four option bytes (99,130,83,99 dec) */
+        /* RFC 951 (BOOTP): in client requests, "...can be a 'generic' name
+         * such as 'unix' or 'gateway'; this means 'boot the named program
+         * configured for my machine'"
+         */
+        /* BOOTP fields end here, BOOTP says optional uint8_t vend[64] follows */
+        uint32_t cookie;      /* DHCP magic bytes: 99,130,83,99 decimal */
         uint8_t options[DHCP_OPTIONS_BUFSIZE + CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS];
 };
 #define DHCP_PKT_SNAME_LEN      64
@@ -142,18 +156,21 @@ struct dhcp_scan_state {
 //#define DHCP_NTP_SERVER       0x2a
 //#define DHCP_WINS_SERVER      0x2c
 #define DHCP_REQUESTED_IP       0x32 /* 50: sent by client if specific IP is wanted */
-#define DHCP_LEASE_TIME         0x33 /* 51: */
-#define DHCP_OPTION_OVERLOAD    0x34 /* 52: */
-#define DHCP_MESSAGE_TYPE       0x35 /* 53: */
+#define DHCP_LEASE_TIME         0x33 /* 51: 32bit big-endian */
+#define DHCP_OPTION_OVERLOAD    0x34 /* 52: 1 byte */
+#define DHCP_MESSAGE_TYPE       0x35 /* 53: 1 byte */
 #define DHCP_SERVER_ID          0x36 /* 54: server's IP */
 #define DHCP_PARAM_REQ          0x37 /* 55: list of options client wants */
 //#define DHCP_ERR_MESSAGE      0x38 /* 56: error message when sending NAK etc */
-#define DHCP_MAX_SIZE           0x39 /* 57: */
+#define DHCP_MAX_SIZE           0x39 /* 57: 16bit big-endian */
+//                              0x3a /* 58: from server: renew time, 32bit big-endian */
+//                              0x3b /* 59: from server: rebind time, 32bit big-endian */
 #define DHCP_VENDOR             0x3c /* 60: client's vendor (a string) */
 #define DHCP_CLIENT_ID          0x3d /* 61: by default client's MAC addr, but may be arbitrarily long */
 //#define DHCP_TFTP_SERVER_NAME 0x42 /* 66: same as 'sname' field */
 //#define DHCP_BOOT_FILE        0x43 /* 67: same as 'file' field */
 //#define DHCP_USER_CLASS       0x4d /* 77: RFC 3004. set of LASCII strings. "I am a printer" etc */
+//                              0x50 /* 80: rapid commit ("I'm ok with getting immediate ACK, not just OFFER"), 0 bytes */
 #define DHCP_FQDN               0x51 /* 81: client asks to update DNS to map its FQDN to its new IP */
 //#define DHCP_PCODE            0x64 /* 100: RFC 4833. IEEE 1003.1 TZ string */
 //#define DHCP_TCODE            0x65 /* 101: RFC 4833. Reference to the TZ database string */
diff --git a/networking/udhcp/dhcpd.c b/networking/udhcp/dhcpd.c
index 91f70970a..0f5edb75c 100644
--- a/networking/udhcp/dhcpd.c
+++ b/networking/udhcp/dhcpd.c
@@ -27,7 +27,7 @@
 //kbuild:lib-$(CONFIG_FEATURE_UDHCP_RFC3397) += domain_codec.o
 
 //usage:#define udhcpd_trivial_usage
-//usage:       "[-fS] [-I ADDR]" IF_FEATURE_UDHCP_PORT(" [-P PORT]") " [CONFFILE]"
+//usage:       "[-fS] [-I ADDR] [-a MSEC]" IF_FEATURE_UDHCP_PORT(" [-P PORT]") " [CONFFILE]"
 //usage:#define udhcpd_full_usage "\n\n"
 //usage:       "DHCP server\n"
 //usage:     "\n        -f      Run in foreground"
@@ -451,6 +451,8 @@ static NOINLINE void read_config(const char *file)
 
         server_data.start_ip = ntohl(server_data.start_ip);
         server_data.end_ip = ntohl(server_data.end_ip);
+        if (server_data.start_ip > server_data.end_ip)
+                bb_error_msg_and_die("bad start/end IP range in %s", file);
 }
 
 static void write_leases(void)
@@ -612,6 +614,10 @@ static void send_packet_to_relay(struct dhcp_packet *dhcp_pkt)
         udhcp_send_kernel_packet(dhcp_pkt,
                         server_data.server_nip, SERVER_PORT,
                         dhcp_pkt->gateway_nip, SERVER_PORT,
+        /* Yes, relay agents receive (and send) all their packets on SERVER_PORT,
+         * even those which are clients' requests and would normally
+         * (i.e. without relay) use CLIENT_PORT. See RFC 1542.
+         */
                         server_data.interface);
 }
 
@@ -858,7 +864,6 @@ int udhcpd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int udhcpd_main(int argc UNUSED_PARAM, char **argv)
 {
         int server_socket = -1, retval;
-        uint8_t *state;
         unsigned timeout_end;
         unsigned num_ips;
         unsigned opt;
@@ -877,6 +882,12 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
         /* Setup the signal pipe on fds 3,4 - must be before openlog() */
         udhcp_sp_setup();
 
+#define OPT_f (1 << 0)
+#define OPT_S (1 << 1)
+#define OPT_I (1 << 2)
+#define OPT_v (1 << 3)
+#define OPT_a (1 << 4)
+#define OPT_P (1 << 5)
         opt = getopt32(argv, "^"
                 "fSI:va:"IF_FEATURE_UDHCP_PORT("P:")
                 "\0"
@@ -887,24 +898,24 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
                 , &str_a
                 IF_FEATURE_UDHCP_PORT(, &str_P)
                 IF_UDHCP_VERBOSE(, &dhcp_verbose)
-                );
-        if (!(opt & 1)) { /* no -f */
+        );
+        if (!(opt & OPT_f)) { /* no -f */
                 bb_daemonize_or_rexec(0, argv);
                 logmode = LOGMODE_NONE;
         }
         /* update argv after the possible vfork+exec in daemonize */
         argv += optind;
-        if (opt & 2) { /* -S */
+        if (opt & OPT_S) {
                 openlog(applet_name, LOG_PID, LOG_DAEMON);
                 logmode |= LOGMODE_SYSLOG;
         }
-        if (opt & 4) { /* -I */
+        if (opt & OPT_I) {
                 len_and_sockaddr *lsa = xhost_and_af2sockaddr(str_I, 0, AF_INET);
                 server_data.server_nip = lsa->u.sin.sin_addr.s_addr;
                 free(lsa);
         }
 #if ENABLE_FEATURE_UDHCP_PORT
-        if (opt & 32) { /* -P */
+        if (opt & OPT_P) {
                 SERVER_PORT = xatou16(str_P);
                 CLIENT_PORT = SERVER_PORT + 1;
         }
@@ -960,6 +971,7 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
                 struct dhcp_packet packet;
                 int bytes;
                 int tv;
+                uint8_t *msg_type;
                 uint8_t *server_id_opt;
                 uint8_t *requested_ip_opt;
                 uint32_t requested_nip;
@@ -1017,6 +1029,9 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
                  * socket read inside this call is restarted on caught signals.
                  */
                 bytes = udhcp_recv_kernel_packet(&packet, server_socket);
+//NB: we do not check source port here. Should we?
+//It should be CLIENT_PORT for clients,
+//or SERVER_PORT for relay agents (in which case giaddr must be != 0.0.0.0)
                 if (bytes < 0) {
                         /* bytes can also be -2 ("bad packet data") */
                         if (bytes == -1 && errno != EINTR) {
@@ -1034,8 +1049,8 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
                         bb_info_msg("not a REQUEST%s", ", ignoring packet");
                         continue;
                 }
-                state = udhcp_get_option(&packet, DHCP_MESSAGE_TYPE);
-                if (state == NULL || state[0] < DHCP_MINTYPE || state[0] > DHCP_MAXTYPE) {
+                msg_type = udhcp_get_option(&packet, DHCP_MESSAGE_TYPE);
+                if (!msg_type || msg_type[0] < DHCP_MINTYPE || msg_type[0] > DHCP_MAXTYPE) {
                         bb_info_msg("no or bad message type option%s", ", ignoring packet");
                         continue;
                 }
@@ -1071,7 +1086,7 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
                         move_from_unaligned32(requested_nip, requested_ip_opt);
                 }
 
-                switch (state[0]) {
+                switch (msg_type[0]) {
 
                 case DHCPDISCOVER:
                         log1("received %s", "DISCOVER");
diff --git a/networking/udhcp/dhcprelay.c b/networking/udhcp/dhcprelay.c
index ef9447b4b..2352c34a2 100644
--- a/networking/udhcp/dhcprelay.c
+++ b/networking/udhcp/dhcprelay.c
@@ -17,7 +17,8 @@
 //usage:#define dhcprelay_trivial_usage
 //usage:       "CLIENT_IFACE[,CLIENT_IFACE2]... SERVER_IFACE [SERVER_IP]"
 //usage:#define dhcprelay_full_usage "\n\n"
-//usage:       "Relay DHCP requests between clients and server"
+//usage:       "Relay DHCP requests between clients and server.\n"
+//usage:       "Without SERVER_IP, requests are broadcast on SERVER_IFACE."
 
 #include "common.h"
 
@@ -31,7 +32,7 @@
 /* This list holds information about clients. The xid_* functions manipulate this list. */
 struct xid_item {
         unsigned timestamp;
-        int client;
+        unsigned iface_no;
         uint32_t xid;
         struct sockaddr_in ip;
         struct xid_item *next;
@@ -40,7 +41,7 @@ struct xid_item {
 #define dhcprelay_xid_list (*(struct xid_item*)bb_common_bufsiz1)
 #define INIT_G() do { setup_common_bufsiz(); } while (0)
 
-static struct xid_item *xid_add(uint32_t xid, struct sockaddr_in *ip, int client)
+static struct xid_item *xid_add(uint32_t xid, struct sockaddr_in *ip, unsigned iface_no)
 {
         struct xid_item *item;
 
@@ -50,7 +51,7 @@ static struct xid_item *xid_add(uint32_t xid, struct sockaddr_in *ip, int client
         /* add xid entry */
         item->ip = *ip;
         item->xid = xid;
-        item->client = client;
+        item->iface_no = iface_no;
         item->timestamp = monotonic_sec();
         item->next = dhcprelay_xid_list.next;
         dhcprelay_xid_list.next = item;
@@ -127,10 +128,10 @@ static int get_dhcp_packet_type(struct dhcp_packet *p)
  * make_iface_list - parses client/server interface names
  * returns array
  */
-static char **make_iface_list(char **client_and_server_ifaces, int *client_number)
+static char **make_iface_list(char **client_and_server_ifaces, unsigned *client_number)
 {
         char *s, **iface_list;
-        int i, cn;
+        unsigned i, cn;
 
         /* get number of items */
         cn = 2; /* 1 server iface + at least 1 client one */
@@ -165,9 +166,9 @@ static char **make_iface_list(char **client_and_server_ifaces, int *client_numbe
 /* Creates listen sockets (in fds) bound to client and server ifaces,
  * and returns numerically max fd.
  */
-static int init_sockets(char **iface_list, int num_clients, int *fds)
+static unsigned init_sockets(char **iface_list, unsigned num_clients, int *fds)
 {
-        int i, n;
+        unsigned i, n;
 
         n = 0;
         for (i = 0; i < num_clients; i++) {
@@ -195,13 +196,14 @@ static int sendto_ip4(int sock, const void *msg, int msg_len, struct sockaddr_in
  * p - packet to send
  * client - number of the client
  */
-static void pass_to_server(struct dhcp_packet *p, int packet_len, int client, int *fds,
+static void pass_to_server(struct dhcp_packet *p, int packet_len, unsigned from_iface_no, int *fds,
                         struct sockaddr_in *client_addr, struct sockaddr_in *server_addr)
 {
         int type;
 
         /* check packet_type */
         type = get_dhcp_packet_type(p);
+//FIXME: the above does not consider packet_len!
         if (type != DHCPDISCOVER && type != DHCPREQUEST
          && type != DHCPDECLINE && type != DHCPRELEASE
          && type != DHCPINFORM
@@ -210,7 +212,10 @@ static void pass_to_server(struct dhcp_packet *p, int packet_len, int client, in
         }
 
         /* create new xid entry */
-        xid_add(p->xid, client_addr, client);
+        xid_add(p->xid, client_addr, from_iface_no);
+//TODO: since we key request/reply pairs on xid values, shouldn't we drop new requests
+//with xid accidentally matching a xid of one of requests we currently hold
+//waiting for their replies?
 
         /* forward request to server */
         /* note that we send from fds[0] which is bound to SERVER_PORT (67).
@@ -229,25 +234,30 @@ static void pass_to_client(struct dhcp_packet *p, int packet_len, int *fds)
         int type;
         struct xid_item *item;
 
-        /* check xid */
-        item = xid_find(p->xid);
-        if (!item) {
-                return;
-        }
-
         /* check packet type */
         type = get_dhcp_packet_type(p);
+//FIXME: the above does not consider packet_len!
         if (type != DHCPOFFER && type != DHCPACK && type != DHCPNAK) {
                 return;
         }
 
+        /* check xid */
+        item = xid_find(p->xid);
+        if (!item) {
+                return;
+        }
+//NB: RFC 1542 section 4.1 seems to envision the logic that
+//relay agents use giaddr (dhcp_msg.gateway_nip in our code)
+//to find out on which interface to reply.
+//(server is meant to copy giaddr from our request packet to its reply).
+//Above, we don't use that logic, instead we use xid as a key.
+
 //TODO: also do it if (p->flags & htons(BROADCAST_FLAG)) is set!
         if (item->ip.sin_addr.s_addr == htonl(INADDR_ANY))
                 item->ip.sin_addr.s_addr = htonl(INADDR_BROADCAST);
 
-        if (sendto_ip4(fds[item->client], p, packet_len, &item->ip) != 0) {
-                return; /* send error occurred */
-        }
+        sendto_ip4(fds[item->iface_no], p, packet_len, &item->ip);
+        /* ^^^ if send error occurred, we can't do much, hence no check */
 
         /* remove xid entry */
         xid_del(p->xid);
@@ -259,7 +269,7 @@ int dhcprelay_main(int argc UNUSED_PARAM, char **argv)
         struct sockaddr_in server_addr;
         char **iface_list;
         int *fds;
-        int num_sockets, max_socket;
+        unsigned num_sockets, max_socket;
         uint32_t our_nip;
 
         INIT_G();
@@ -293,7 +303,7 @@ int dhcprelay_main(int argc UNUSED_PARAM, char **argv)
 // every N minutes?
                 fd_set rfds;
                 struct timeval tv;
-                int i;
+                unsigned i;
 
                 FD_ZERO(&rfds);
                 for (i = 0; i < num_sockets; i++)
@@ -304,15 +314,17 @@ int dhcprelay_main(int argc UNUSED_PARAM, char **argv)
                         int packlen;
                         struct dhcp_packet dhcp_msg;
 
-                        /* server */
+                        /* from server */
                         if (FD_ISSET(fds[0], &rfds)) {
                                 packlen = udhcp_recv_kernel_packet(&dhcp_msg, fds[0]);
+//NB: we do not check source port here. Should we?
+//It should be SERVER_PORT.
                                 if (packlen > 0) {
                                         pass_to_client(&dhcp_msg, packlen, fds);
                                 }
                         }
 
-                        /* clients */
+                        /* from clients */
                         for (i = 1; i < num_sockets; i++) {
                                 struct sockaddr_in client_addr;
                                 socklen_t addr_size;
@@ -325,6 +337,11 @@ int dhcprelay_main(int argc UNUSED_PARAM, char **argv)
                                                 (struct sockaddr *)(&client_addr), &addr_size);
                                 if (packlen <= 0)
                                         continue;
+//NB: we do not check source port here. Should we?
+//It should be CLIENT_PORT for clients.
+//It can be SERVER_PORT for relay agents (in which case giaddr must be != 0.0.0.0),
+//but is it even supported to chain relay agents like this?
+//(we still copy client_addr.port and use it to reply to the port we got request from)
 
                                 /* Get our IP on corresponding client_iface */
 // RFC 1542