dhcprelay: fix usage text. Simplify and make code more readable.
Add TODOs.
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 @@
}
-/* 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 @@
/**
- * 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 @@
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 @@
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 @@
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 @@
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();
- }
-}
+ } /* while (1) */
-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;
-
- /* doesn't return */
- dhcprelay_loop(fds, num_sockets, max_socket, clients, &server_addr, gw_ip);
/* return 0; - not reached */
}