From e8a796828eee4b898be2141ecbe34bad594bfbbb Mon Sep 17 00:00:00 2001 From: Denis Vlasenko Date: Mon, 13 Apr 2009 03:33:46 +0000 Subject: dhcprelay: fix usage text. Simplify and make code more readable. Add TODOs. --- networking/udhcp/dhcprelay.c | 135 +++++++++++++++++++++++-------------------- 1 file changed, 73 insertions(+), 62 deletions(-) (limited to 'networking') diff --git a/networking/udhcp/dhcprelay.c b/networking/udhcp/dhcprelay.c index f3b2855..53540d1 100644 --- a/networking/udhcp/dhcprelay.c +++ b/networking/udhcp/dhcprelay.c @@ -13,7 +13,6 @@ #include "common.h" #include "options.h" -/* constants */ #define SERVER_PORT 67 #define SELECT_TIMEOUT 5 /* select timeout in sec. */ #define MAX_LIFETIME 2*60 /* lifetime of an xid entry in sec. */ @@ -149,19 +148,21 @@ static char **get_client_devices(char *dev_list, int *client_number) } -/* Creates listen sockets (in fds) and returns numerically max fd. */ -static int init_sockets(char **client, int num_clients, - char *server, int *fds) +/* Creates listen sockets (in fds) bound to client and server ifaces, + * and returns numerically max fd. + */ +static int init_sockets(char **client_ifaces, int num_clients, + char *server_iface, int *fds) { int i, n; /* talk to real server on bootps */ - fds[0] = udhcp_listen_socket(/*INADDR_ANY,*/ SERVER_PORT, server); + fds[0] = udhcp_listen_socket(/*INADDR_ANY,*/ SERVER_PORT, server_iface); n = fds[0]; for (i = 1; i < num_clients; i++) { /* listen for clients on bootps */ - fds[i] = udhcp_listen_socket(/*INADDR_ANY,*/ SERVER_PORT, client[i-1]); + fds[i] = udhcp_listen_socket(/*INADDR_ANY,*/ SERVER_PORT, client_ifaces[i-1]); if (fds[i] > n) n = fds[i]; } @@ -170,11 +171,11 @@ static int init_sockets(char **client, int num_clients, /** - * pass_on() - forwards dhcp packets from client to server + * pass_to_server() - forwards dhcp packets from client to server * p - packet to send * client - number of the client */ -static void pass_on(struct dhcpMessage *p, int packet_len, int client, int *fds, +static void pass_to_server(struct dhcpMessage *p, int packet_len, int client, int *fds, struct sockaddr_in *client_addr, struct sockaddr_in *server_addr) { int res, type; @@ -193,19 +194,19 @@ static void pass_on(struct dhcpMessage *p, int packet_len, int client, int *fds, item = xid_add(p->xid, client_addr, client); /* forward request to LAN (server) */ + errno = 0; res = sendto(fds[0], p, packet_len, 0, (struct sockaddr*)server_addr, sizeof(struct sockaddr_in)); if (res != packet_len) { - bb_perror_msg("pass_on"); - return; + bb_perror_msg("sendto"); } } /** - * pass_back() - forwards dhcp packets from server to client + * pass_to_client() - forwards dhcp packets from server to client * p - packet to send */ -static void pass_back(struct dhcpMessage *p, int packet_len, int *fds) +static void pass_to_client(struct dhcpMessage *p, int packet_len, int *fds) { int res, type; struct xid_item *item; @@ -224,10 +225,11 @@ static void pass_back(struct dhcpMessage *p, int packet_len, int *fds) if (item->ip.sin_addr.s_addr == htonl(INADDR_ANY)) item->ip.sin_addr.s_addr = htonl(INADDR_BROADCAST); - res = sendto(fds[item->client], p, packet_len, 0, (struct sockaddr*)(&item->ip), - sizeof(item->ip)); + errno = 0; + res = sendto(fds[item->client], p, packet_len, 0, (struct sockaddr*) &(item->ip), + sizeof(item->ip)); if (res != packet_len) { - bb_perror_msg("pass_back"); + bb_perror_msg("sendto"); return; } @@ -235,20 +237,53 @@ static void pass_back(struct dhcpMessage *p, int packet_len, int *fds) xid_del(p->xid); } -static void dhcprelay_loop(int *fds, int num_sockets, int max_socket, char **clients, - struct sockaddr_in *server_addr, uint32_t gw_ip) NORETURN; -static void dhcprelay_loop(int *fds, int num_sockets, int max_socket, char **clients, - struct sockaddr_in *server_addr, uint32_t gw_ip) +int dhcprelay_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; +int dhcprelay_main(int argc, char **argv) { struct dhcpMessage dhcp_msg; - fd_set rfds; - size_t packlen; - socklen_t addr_size; + struct sockaddr_in server_addr; struct sockaddr_in client_addr; - struct timeval tv; - int i; + fd_set rfds; + char **client_ifaces; + int *fds; + int num_sockets, max_socket; + uint32_t our_ip; + + server_addr.sin_family = AF_INET; + server_addr.sin_port = htons(SERVER_PORT); + + /* dhcprelay client_iface1,client_iface2,... server_iface [server_IP] */ + if (argc == 4) { + if (!inet_aton(argv[3], &server_addr.sin_addr)) + bb_perror_msg_and_die("bad server IP"); + } else if (argc == 3) { + server_addr.sin_addr.s_addr = htonl(INADDR_BROADCAST); + } else { + bb_show_usage(); + } + + /* Produce list of client ifaces */ + client_ifaces = get_client_devices(argv[1], &num_sockets); + + num_sockets++; /* for server socket at fds[0] */ + fds = xmalloc(num_sockets * sizeof(fds[0])); + + /* Create sockets and bind one to every iface */ + max_socket = init_sockets(client_ifaces, num_sockets, argv[2], fds); + + /* Get our IP on server_iface */ + if (udhcp_read_interface(argv[2], NULL, &our_ip, NULL)) + return 1; + /* Main loop */ while (1) { +//reinit stuff from time to time? go back to get_client_devices +//every N minutes? + struct timeval tv; + size_t packlen; + socklen_t addr_size; + int i; + FD_ZERO(&rfds); for (i = 0; i < num_sockets; i++) FD_SET(fds[i], &rfds); @@ -259,56 +294,32 @@ static void dhcprelay_loop(int *fds, int num_sockets, int max_socket, char **cli if (FD_ISSET(fds[0], &rfds)) { packlen = udhcp_recv_kernel_packet(&dhcp_msg, fds[0]); if (packlen > 0) { - pass_back(&dhcp_msg, packlen, fds); + pass_to_client(&dhcp_msg, packlen, fds); } } + /* clients */ for (i = 1; i < num_sockets; i++) { - /* clients */ if (!FD_ISSET(fds[i], &rfds)) continue; addr_size = sizeof(struct sockaddr_in); packlen = recvfrom(fds[i], &dhcp_msg, sizeof(dhcp_msg), 0, - (struct sockaddr *)(&client_addr), &addr_size); + (struct sockaddr *)(&client_addr), &addr_size); if (packlen <= 0) continue; - if (udhcp_read_interface(clients[i-1], NULL, &dhcp_msg.giaddr, NULL)) - dhcp_msg.giaddr = gw_ip; - pass_on(&dhcp_msg, packlen, i, fds, &client_addr, server_addr); + + /* Get our IP on corresponding client_iface */ +//why? what if server can't route such IP? + if (udhcp_read_interface(client_ifaces[i-1], NULL, &dhcp_msg.giaddr, NULL)) { + /* Fall back to our server_iface's IP */ +//this makes more sense! + dhcp_msg.giaddr = our_ip; + } +//maybe set dhcp_msg.flags |= BROADCAST_FLAG too? + pass_to_server(&dhcp_msg, packlen, i, fds, &client_addr, &server_addr); } } xid_expire(); - } -} - -int dhcprelay_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; -int dhcprelay_main(int argc, char **argv) -{ - int num_sockets, max_socket; - int *fds; - uint32_t gw_ip; - char **clients; - struct sockaddr_in server_addr; - - server_addr.sin_family = AF_INET; - server_addr.sin_port = htons(SERVER_PORT); - if (argc == 4) { - if (!inet_aton(argv[3], &server_addr.sin_addr)) - bb_perror_msg_and_die("didn't grok server"); - } else if (argc == 3) { - server_addr.sin_addr.s_addr = htonl(INADDR_BROADCAST); - } else { - bb_show_usage(); - } - - clients = get_client_devices(argv[1], &num_sockets); - num_sockets++; /* for server socket at fds[0] */ - fds = xmalloc(num_sockets * sizeof(fds[0])); - max_socket = init_sockets(clients, num_sockets, argv[2], fds); - - if (udhcp_read_interface(argv[2], NULL, &gw_ip, NULL)) - return 1; + } /* while (1) */ - /* doesn't return */ - dhcprelay_loop(fds, num_sockets, max_socket, clients, &server_addr, gw_ip); /* return 0; - not reached */ } -- cgit v1.1