2 * resend.c (C) 1995-1998 Darren Reed
4 * This was written to test what size TCP fragments would get through
5 * various TCP/IP packet filters, as used in IP firewalls. In certain
6 * conditions, enough of the TCP header is missing for unpredictable
7 * results unless the filter is aware that this can happen.
9 * See the IPFILTER.LICENCE file for details on licencing.
11 #if defined(__sgi) && (IRIX > 602)
12 # include <sys/ptimers.h>
19 #include <sys/types.h>
21 #include <sys/socket.h>
23 #include <netinet/in.h>
24 #include <arpa/inet.h>
25 #include <netinet/in_systm.h>
26 #include <netinet/ip.h>
27 #include <netinet/tcp.h>
28 #include <netinet/udp.h>
29 #include <netinet/ip_icmp.h>
31 # include <netinet/ip_var.h>
32 # include <netinet/if_ether.h>
33 # if __FreeBSD_version >= 300000
34 # include <net/if_var.h>
40 static const char sccsid
[] = "@(#)resend.c 1.3 1/11/96 (C)1995 Darren Reed";
41 static const char rcsid
[] = "@(#)$Id: resend.c,v 2.1.4.5 2002/12/06 11:40:36 darrenr Exp $";
47 static u_char pbuf
[65536]; /* 1 big packet */
48 void printpacket
__P((ip_t
*));
57 t
= (tcphdr_t
*)((char *)ip
+ (ip
->ip_hl
<< 2));
59 printf("tos %#x ", ip
->ip_tos
);
60 if (ip
->ip_off
& 0x3fff)
61 printf("frag @%#x ", (ip
->ip_off
& 0x1fff) << 3);
62 printf("len %d id %d ", ip
->ip_len
, ip
->ip_id
);
63 printf("ttl %d p %d src %s", ip
->ip_ttl
, ip
->ip_p
,
64 inet_ntoa(ip
->ip_src
));
65 if (ip
->ip_p
== IPPROTO_TCP
|| ip
->ip_p
== IPPROTO_UDP
)
66 printf(",%d", t
->th_sport
);
67 printf(" dst %s", inet_ntoa(ip
->ip_dst
));
68 if (ip
->ip_p
== IPPROTO_TCP
|| ip
->ip_p
== IPPROTO_UDP
)
69 printf(",%d", t
->th_dport
);
70 if (ip
->ip_p
== IPPROTO_TCP
) {
71 printf(" seq %lu:%lu flags ",
72 (u_long
)t
->th_seq
, (u_long
)t
->th_ack
);
73 for (j
= 0, i
= 1; i
< 256; i
*= 2, j
++)
75 printf("%c", "FSRPAU--"[j
]);
81 int ip_resend(dev
, mtu
, r
, gwip
, datain
)
91 int fd
, wfd
= initdevice(dev
, 0, 5), len
, i
;
94 fd
= (*r
->r_open
)(datain
);
96 fd
= (*r
->r_open
)("-");
101 ip
= (struct ip
*)pbuf
;
102 eh
= (ether_header_t
*)malloc(sizeof(*eh
));
105 perror("malloc failed");
109 bzero((char *)A_A eh
->ether_shost
, sizeof(eh
->ether_shost
));
110 if (gwip
.s_addr
&& (arp((char *)&gwip
, dhost
) == -1))
116 while ((i
= (*r
->r_readip
)((char *)pbuf
, sizeof(pbuf
), NULL
, NULL
)) > 0)
118 if (!(opts
& OPT_RAW
)) {
119 len
= ntohs(ip
->ip_len
);
120 eh
= (ether_header_t
*)realloc((char *)eh
, sizeof(*eh
) + len
);
121 eh
->ether_type
= htons((u_short
)ETHERTYPE_IP
);
123 if (arp((char *)&gwip
,
124 (char *)A_A eh
->ether_dhost
) == -1) {
129 bcopy(dhost
, (char *)A_A eh
->ether_dhost
,
132 ip
->ip_sum
= chksum((u_short
*)ip
,
134 bcopy(ip
, (char *)(eh
+ 1), len
);
138 eh
= (ether_header_t
*)pbuf
;
142 if (sendip(wfd
, (char *)eh
, len
) == -1)
144 perror("send_packet");