请问如何获得router IP

asang · 发表于 2006-4-27 15:47:39

请问如何获得router IP

我碰到的问题是这样的
有一台中心服务器(有公网固定IP)
客户端PC(通过路由器+adsl上网)

现在服务器端想获得客户端PC的路由器的IP,
不知道怎么实现?

谢谢

Arthur.Echo · 发表于 2006-4-27 16:16:26

route信息记录在/proc/net/route文件中，你可以像ps一样直接打开这个文件从该文件中读到router的IP

Agadoo · 发表于 2006-4-27 20:21:59

/*
* file: scanroute.c
* date:2006 - 4- 26
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <netdb.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in_systm.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#define __FAVOR_BSD
#include <netinet/udp.h>
#include <arpa/inet.h>
enum {CMD_NAME, DST_IP};
enum {ON, OFF};
#define MAXHOSTNAMELEN 256
#define BUFSIZE 512
struct packet_udp
{
struct ip ip;
struct udphdr udp;
};
void make_ip_header(struct ip *ip, int src_ip, int dst_ip, int ip_len);
void make_udp_header(struct udphdr *udp);
void tvsub(struct timeval *out, struct timeval *in);
u_short checksum(u_short *data, int len);
int main(int argc, char * argv[])
{
struct packet_udp sendpacket; /* UDP packet to be sent */
struct sockaddr_in send_sa;
int send_sd;
int recv_sd;
int len;
int ttl;
int i;
u_char buff[BUFSIZE];
struct timeval tvm0; /* the time packet sent */
struct timeval tvm1; /* the time packet received */
struct timeval tv; /* (select)'s time out */
fd_set readfd; /* descriptor for (select) check */
int on = 1;
int dns_flg = ON; /* whether to resolve host's domain name */
/* check arg "-n" */
if(argc == 3 && (strcmp(argv[1], "-n") == 0))
{
dns_flg = OFF;
argv[1] = argv[2];
argv[2] = NULL;
argc = 2;
}
if(argc != 2)
{
fprintf(stderr, "usage: %s [-n] dst_ip \n", argv[CMD_NAME]);
exit(EXIT_FAILURE);
}
memset((char *)&send_sa, 0, sizeof(struct sockaddr_in));
send_sa.sin_family = AF_INET;
/* convert domain name to IP */
if((send_sa.sin_addr.s_addr = inet_addr(argv[DST_IP])) == INADDR_NONE)
{
struct hostent *he;
if((he = gethostbyname(argv[DST_IP])) == NULL)
{
fprintf(stderr, "unknow host %s \n", argv[DST_IP]);
exit(EXIT_FAILURE);
}
send_sa.sin_family = he->h_addrtype;
memcpy((char*)&(send_sa.sin_addr), he->h_addr, sizeof(he->h_length));
}
/* open a RAW socket for UDP to send */
if((send_sd = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0)
{
perror("socket(RAW)");
exit(EXIT_FAILURE);
}
if(setsockopt(send_sd, IPPROTO_IP, IP_HDRINCL, &on, sizeof(on)) < 0)
{
perror("setsockopt(IPPROTO_IP, IP_HDRINCL)");
exit(EXIT_FAILURE);
}
/* open a RAW socket for ICMP to receive */
if((recv_sd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP)) < 0)
{
perror("socket(SOCK_RAW)");
exit(EXIT_FAILURE);
}
/* generate a UDP packet */
len = sizeof(struct packet_udp);
memset((char*)&sendpacket, 0, sizeof(struct packet_udp));
make_udp_header(&(sendpacket.udp));
make_ip_header(&(sendpacket.ip), 0, send_sa.sin_addr.s_addr, len);
/* main routine */
printf("Scanroute %s \n", inet_ntoa(send_sa.sin_addr));
for(ttl = 1; ttl <= 64; ttl++)
{
printf("%2d: ", ttl);
fflush(stdout);
sendpacket.ip.ip_ttl = ttl;
for(i = 0; i < 3; i++)
{
/* send a UDP packet */
if(sendto(send_sd, (char*)&sendpacket, len, 0,
(struct sockaddr *)&send_sa, sizeof(send_sa)) < 0)
{
perror("sendto");
exit(EXIT_FAILURE);
}
/* store the time sent */
gettimeofday(&tvm0, (struct timezone *)0);
/* set time out */
tv.tv_sec = 3;
tv.tv_usec = 0;
reread:
/* check descriptors using "select" */
FD_ZERO(&readfd);
FD_SET(recv_sd, &readfd);
if((select(recv_sd+1, &readfd, NULL, NULL, &tv)) > 0)
{
int hlen; /* len of header */
struct icmp *icmp;
struct ip *ip;
struct hostent *host;
char hostip[256];
struct in_addr ipaddr;
/* receive a ICMP packet */
if(recvfrom(recv_sd, buff, BUFSIZE, 0, NULL, NULL) < 0)
{
perror("recvfrom");
exit(EXIT_FAILURE);
}
ip = (struct ip *)buff;
hlen = ip->ip_hl << 2;
if(ip->ip_p != IPPROTO_ICMP)
goto reread;
icmp = (struct icmp *)(buff + hlen);
/* don't receive unrelated packets */
if((icmp->icmp_type != ICMP_TIMXCEED
|| icmp->icmp_code != ICMP_TIMXCEED_INTRANS)
&& (icmp->icmp_type != ICMP_UNREACH_PORT))
goto reread;
/* store the time received packet */
gettimeofday(&tvm1, (struct timezone *)0);
tvsub(&tvm1, &tvm0);
memcpy(&ipaddr, &(ip->ip_src.s_addr), sizeof(ipaddr));
strcpy(hostip, inet_ntoa(*(struct in_addr *)&(ip->ip_src.s_addr)));
/* display IP and domain name */
if(dns_flg == OFF)
printf("% -15s", hostip);
else if((host= gethostbyaddr((char*)&ipaddr, 4, AF_INET)) == NULL)
printf("%-15s(%S)", hostip, hostip);
else
printf("%-15s(%S)", hostip, host->h_name);
printf(":RTT= %8.4fms", tvm1.tv_sec*1000.0 + tvm1.tv_usec/1000.0);
/* check whether reached dst host */
if(icmp->icmp_type == ICMP_UNREACH_PORT)
{
printf("\n Reach!\n");
goto exit;
}
else
break;
}
else
{
printf("?");
fflush(stdout);
}
}
printf(" \n");
}
exit:
close(send_sd);
close(recv_sd);
return EXIT_SUCCESS;
}
/*************************************************/
void make_udp_header(struct udphdr *udp)
{
udp->uh_sport = htons(0);
udp->uh_ulen = htons((u_short)sizeof(struct udphdr));
udp->uh_dport = htons(33434); /* port of traceroute */
udp->uh_sum = htons(0);
}
void make_ip_header(struct ip *ip, int src_ip, int dst_ip, int ip_len)
{
memset((char *)ip, 0, sizeof(struct ip));
/* generate an IP header */
ip->ip_v = IPVERSION;
ip->ip_hl = sizeof(struct ip) >> 2;
ip->ip_id = htons(0);
ip->ip_off = 0;
#ifdef _linux
/* linux's RAW IP */
ip->ip_len = htons(ip_len);
ip->ip_off = htons(0);
#else
/* BSD's RAW IP */
ip->ip_len = ip_len;
ip->ip_off = 0;
#endif
ip->ip_ttl = 64;
ip->ip_p = IPPROTO_UDP;
ip->ip_src.s_addr = src_ip;
ip->ip_dst.s_addr = dst_ip;
/* calc the checksum */
ip->ip_sum = 0;
ip->ip_sum = checksum((u_short *)ip, sizeof(struct ip));
}
void tvsub(struct timeval *out, struct timeval * in)
{
if( (out->tv_usec -= in->tv_usec) < 0)
{
out->tv_sec --;
out->tv_usec += 1000000;
}
out->tv_sec -= in->tv_sec;
}
u_short checksum(u_short *data, int len)
{
u_long sum = 0;
/* increase 2 bytes at one time */
for(; len > 1; len -= 2)
{
sum += *data++;
if(sum & 0x80000000)
sum = (sum & 0xffff) + (sum >> 16);
}
/* process if len is odd */
if(len == 1)
{
u_short i = 0;
*(u_char *)(&i) = * (u_char *)data;
sum += i;
}
/* process the overflow bit */
while(sum >> 16)
sum = (sum & 0xffff) + (sum >> 16);
return (sum == 0xffff) ? sum : ~sum;
}

复制代码

Arthur.Echo · 发表于 2006-4-28 09:03:05

Post by Agadoo

/*

* file: scanroute.c

* date:2006 - 4- 26

*/

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <netdb.h>

#include <sys/time.h>

#include <sys/socket.h>

#include <sys/types.h>

#include <netinet/in_systm.h>

#include <netinet/in.h>

#include <netinet/ip.h>

#include <netinet/ip_icmp.h>

#define __FAVOR_BSD

#include <netinet/udp.h>

#include <arpa/inet.h>

enum {CMD_NAME, DST_IP};

enum {ON, OFF};

#define MAXHOSTNAMELEN 256

#define BUFSIZE 512

struct packet_udp

{

struct ip ip;

struct udphdr udp;

};

void make_ip_header(struct ip *ip, int src_ip, int dst_ip, int ip_len);

void make_udp_header(struct udphdr *udp);

void tvsub(struct timeval *out, struct timeval *in);

u_short checksum(u_short *data, int len);

int main(int argc, char * argv[])

{

struct packet_udp sendpacket; /* UDP packet to be sent */

struct sockaddr_in send_sa;

int send_sd;

int recv_sd;

int len;

int ttl;

int i;

u_char buff[BUFSIZE];

struct timeval tvm0; /* the time packet sent */

struct timeval tvm1; /* the time packet received */

struct timeval tv; /* (select)'s time out */

fd_set readfd; /* descriptor for (select) check */

int on = 1;

int dns_flg = ON; /* whether to resolve host's domain name */

/* check arg "-n" */

if(argc == 3 && (strcmp(argv[1], "-n") == 0))

{

dns_flg = OFF;

argv[1] = argv[2];

argv[2] = NULL;

argc = 2;

}

if(argc != 2)

{

fprintf(stderr, "usage: %s [-n] dst_ip \n", argv[CMD_NAME]);

exit(EXIT_FAILURE);

}

memset((char *)&send_sa, 0, sizeof(struct sockaddr_in));

send_sa.sin_family = AF_INET;

/* convert domain name to IP */

if((send_sa.sin_addr.s_addr = inet_addr(argv[DST_IP])) == INADDR_NONE)

{

struct hostent *he;

if((he = gethostbyname(argv[DST_IP])) == NULL)

{

fprintf(stderr, "unknow host %s \n", argv[DST_IP]);

exit(EXIT_FAILURE);

}

send_sa.sin_family = he->h_addrtype;

memcpy((char*)&(send_sa.sin_addr), he->h_addr, sizeof(he->h_length));

}

/* open a RAW socket for UDP to send */

if((send_sd = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0)

{

perror("socket(RAW)");

exit(EXIT_FAILURE);

}

if(setsockopt(send_sd, IPPROTO_IP, IP_HDRINCL, &on, sizeof(on)) < 0)

{

perror("setsockopt(IPPROTO_IP, IP_HDRINCL)");

exit(EXIT_FAILURE);

}

/* open a RAW socket for ICMP to receive */

if((recv_sd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP)) < 0)

{

perror("socket(SOCK_RAW)");

exit(EXIT_FAILURE);

}

/* generate a UDP packet */

len = sizeof(struct packet_udp);

memset((char*)&sendpacket, 0, sizeof(struct packet_udp));

make_udp_header(&(sendpacket.udp));

make_ip_header(&(sendpacket.ip), 0, send_sa.sin_addr.s_addr, len);

/* main routine */

printf("Scanroute %s \n", inet_ntoa(send_sa.sin_addr));

for(ttl = 1; ttl <= 64; ttl++)

{

printf("%2d: ", ttl);

fflush(stdout);

sendpacket.ip.ip_ttl = ttl;

for(i = 0; i < 3; i++)

{

/* send a UDP packet */

if(sendto(send_sd, (char*)&sendpacket, len, 0,

(struct sockaddr *)&send_sa, sizeof(send_sa)) < 0)

{

perror("sendto");

exit(EXIT_FAILURE);

}

/* store the time sent */

gettimeofday(&tvm0, (struct timezone *)0);

/* set time out */

tv.tv_sec = 3;

tv.tv_usec = 0;

reread:

/* check descriptors using "select" */

FD_ZERO(&readfd);

FD_SET(recv_sd, &readfd);

if((select(recv_sd+1, &readfd, NULL, NULL, &tv)) > 0)

{

int hlen; /* len of header */

struct icmp *icmp;

struct ip *ip;

struct hostent *host;

char hostip[256];

struct in_addr ipaddr;

/* receive a ICMP packet */

if(recvfrom(recv_sd, buff, BUFSIZE, 0, NULL, NULL) < 0)

{

perror("recvfrom");

exit(EXIT_FAILURE);

}

ip = (struct ip *)buff;

hlen = ip->ip_hl << 2;

if(ip->ip_p != IPPROTO_ICMP)

goto reread;

icmp = (struct icmp *)(buff + hlen);

/* don't receive unrelated packets */

if((icmp->icmp_type != ICMP_TIMXCEED

|| icmp->icmp_code != ICMP_TIMXCEED_INTRANS)

&& (icmp->icmp_type != ICMP_UNREACH_PORT))

goto reread;

/* store the time received packet */

gettimeofday(&tvm1, (struct timezone *)0);

tvsub(&tvm1, &tvm0);

memcpy(&ipaddr, &(ip->ip_src.s_addr), sizeof(ipaddr));

strcpy(hostip, inet_ntoa(*(struct in_addr *)&(ip->ip_src.s_addr)));

/* display IP and domain name */

if(dns_flg == OFF)

printf("% -15s", hostip);

else if((host= gethostbyaddr((char*)&ipaddr, 4, AF_INET)) == NULL)

printf("%-15s(%S)", hostip, hostip);

else

printf("%-15s(%S)", hostip, host->h_name);

printf(":RTT= %8.4fms", tvm1.tv_sec*1000.0 + tvm1.tv_usec/1000.0);

/* check whether reached dst host */

if(icmp->icmp_type == ICMP_UNREACH_PORT)

{

printf("\n Reach!\n");

goto exit;

}

else

break;

}

else

{

printf("?");

fflush(stdout);

}

}

printf(" \n");

}

exit:

close(send_sd);

close(recv_sd);

return EXIT_SUCCESS;

}

/*************************************************/

void make_udp_header(struct udphdr *udp)

{

udp->uh_sport = htons(0);

udp->uh_ulen = htons((u_short)sizeof(struct udphdr));

udp->uh_dport = htons(33434); /* port of traceroute */

udp->uh_sum = htons(0);

}

void make_ip_header(struct ip *ip, int src_ip, int dst_ip, int ip_len)

{

memset((char *)ip, 0, sizeof(struct ip));

/* generate an IP header */

ip->ip_v = IPVERSION;

ip->ip_hl = sizeof(struct ip) >> 2;

ip->ip_id = htons(0);

ip->ip_off = 0;

#ifdef _linux

/* linux's RAW IP */

ip->ip_len = htons(ip_len);

ip->ip_off = htons(0);

#else

/* BSD's RAW IP */

ip->ip_len = ip_len;

ip->ip_off = 0;

#endif

ip->ip_ttl = 64;

ip->ip_p = IPPROTO_UDP;

ip->ip_src.s_addr = src_ip;

ip->ip_dst.s_addr = dst_ip;

/* calc the checksum */

ip->ip_sum = 0;

ip->ip_sum = checksum((u_short *)ip, sizeof(struct ip));

}

void tvsub(struct timeval *out, struct timeval * in)

{

if( (out->tv_usec -= in->tv_usec) < 0)

{

out->tv_sec --;

out->tv_usec += 1000000;

}

out->tv_sec -= in->tv_sec;

}

u_short checksum(u_short *data, int len)

{

u_long sum = 0;

/* increase 2 bytes at one time */

for(; len > 1; len -= 2)

{

sum += *data++;

if(sum & 0x80000000)

sum = (sum & 0xffff) + (sum >> 16);

}

/* process if len is odd */

if(len == 1)

{

u_short i = 0;

*(u_char *)(&i) = * (u_char *)data;

sum += i;

}

/* process the overflow bit */

while(sum >> 16)

sum = (sum & 0xffff) + (sum >> 16);

return (sum == 0xffff) ? sum : ~sum;

}

复制代码

没有看完，但是总体上漂了一眼觉得就是自己来填充数据包的头,我觉得这样是做不到的,因为你的router要通过adsl上网,无论你把数据报的头填成什么样,最终会被NAT修改的.我觉得应该像STUN一样将router的IP用数据的形式告诉服务器.

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请问如何获得router IP

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请问如何获得router IP

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