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dhcprelay: fix usage text. Simplify and make code more readable.

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Add TODOs.
This commit is contained in:
Denis Vlasenko 2009-04-13 03:33:46 +00:00
parent 1f63229a8e
commit e8a796828e
2 changed files with 75 additions and 65 deletions
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5
include/usage.h
View File

@ -802,10 +802,9 @@
"/dev/sda3 17381728 17107080 274648 98% /\n"
#define dhcprelay_trivial_usage \
"[client1,client2,...] [server_device]"
"CLIENT_IFACE[,CLIENT_IFACE2...] SERVER_IFACE [SERVER_IP]"
#define dhcprelay_full_usage "\n\n" \
"Relay dhcp requests from client devices to server device.\n" \
"Pass clients as CSV"
"Relay DHCP requests between clients and server" \
#define diff_trivial_usage \
"[-abdiNqrTstw] [-L LABEL] [-S FILE] [-U LINES] FILE1 FILE2"

127
networking/udhcp/dhcprelay.c
View File

@ -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),
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;
struct sockaddr_in server_addr;
struct sockaddr_in client_addr;
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;
struct sockaddr_in client_addr;
struct timeval tv;
int i;
while (1) {
FD_ZERO(&rfds);
for (i = 0; i < num_sockets; i++)
FD_SET(fds[i], &rfds);
@ -259,11 +294,11 @@ 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);
}
}
for (i = 1; i < num_sockets; i++) {
/* clients */
for (i = 1; i < num_sockets; i++) {
if (!FD_ISSET(fds[i], &rfds))
continue;
addr_size = sizeof(struct sockaddr_in);
@ -271,44 +306,20 @@ static void dhcprelay_loop(int *fds, int num_sockets, int max_socket, char **cli
(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 */
}