rcvmsg.c

mobile ip 在linux下的一种实现

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h> /* for memset */
#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>
#include <unistd.h>
#include "fixed_fd_zero.h"
#include "msgparser.h"

#define DEFAULT_PORT 434
#define MAXMSG 2048

int main(int argc, char *argv[])
{
	int reg_sock;
	struct sockaddr_in serv_addr, cli_addr;
	unsigned int cli_len;
	char msg[MAXMSG];
	int n;
	fd_set set;
	int port;
	struct msg_extensions ext;

	if (argc > 1) {
		port = atoi(argv[1]);
	} else {
		port = DEFAULT_PORT;
	}



	if ((reg_sock = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
		perror("socket");
		exit(-1);
	}

	/*
	 * bind the address and port to listen to
	 */
	memset((char *) &serv_addr, 0, sizeof(serv_addr));
	serv_addr.sin_family = AF_INET;
	serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
	serv_addr.sin_port = htons(port);
	if (bind(reg_sock, (struct sockaddr *) &serv_addr,
		 sizeof(serv_addr)) < 0) {
		perror("bind");
		exit(-1);
	}

	for (;;) {

	  	FD_ZERO(&set);
		FD_SET(reg_sock, &set);
		select(FD_SETSIZE, &set, NULL, NULL, 0);

		memset(&cli_addr, 0, sizeof(cli_addr));
		cli_len = sizeof(cli_addr);
		n = recvfrom(reg_sock, msg, MAXMSG, 0,
			     (struct sockaddr*)&cli_addr, &cli_len);

		printf("Received %d bytes from %s:%d (%d)\n", n,
		       inet_ntoa(cli_addr.sin_addr),
		       ntohs(cli_addr.sin_port),
		       cli_len);

		if (FD_ISSET(reg_sock, &set)) {

		  	parse_msg(msg, n, &ext);

			/*
			 * Show what we got
			 */
			printf("Message is Registration ");
			if (ext.req) {
				printf("Request - id0=%08x , id1=%08x\n",
				       (unsigned int) ntohl(ext.req->id[0]),
				       (unsigned int) ntohl(ext.req->id[1]));
			}
			if (ext.rep) {
				printf("Reply\n");
			}

			if (ext.mh_auth || ext.mf_auth || ext.fa_pubkey ||
			    ext.mn_keyrep || ext.fa_pubkeyrep) {
				printf("And has the following extensions:\n");
				if (ext.mh_auth) {
					printf("\tMobile-Home Authentication"
					       "\n");
				}
				if (ext.mf_auth) {
					printf("\tMobile-Foreign "
					       "Authentication\n");
				}
				if (ext.fa_pubkey) {
					printf("\tFA Public Key\n");
				}
				if (ext.mn_keyrep) {
					printf("\tSession Key to MN\n");
				}
				if (ext.fa_pubkeyrep) {
					printf("\tSession Key to FA (pub)\n");
				}
			} else {
				printf("And has no extensions\n");
			}

		} /* if we got registration request or reply */
	} /* loop forever waiting for messages */
}