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minix/servers/inet/generic/ip_read.c
Kees van Reeuwijk 1597e701a0 Remove useless variables and the computations on them.
2010-02-19 10:00:32 +00:00

1048 lines
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/*
ip_read.c
Copyright 1995 Philip Homburg
*/
#include "inet.h"
#include "buf.h"
#include "clock.h"
#include "event.h"
#include "type.h"
#include "assert.h"
#include "icmp_lib.h"
#include "io.h"
#include "ip.h"
#include "ip_int.h"
#include "ipr.h"
THIS_FILE
FORWARD ip_ass_t *find_ass_ent ARGS(( ip_port_t *ip_port, U16_t id,
int proto, ipaddr_t src, ipaddr_t dst ));
FORWARD acc_t *merge_frags ARGS(( acc_t *first, acc_t *second ));
FORWARD int ip_frag_chk ARGS(( acc_t *pack ));
FORWARD acc_t *reassemble ARGS(( ip_port_t *ip_port, acc_t *pack,
ip_hdr_t *ip_hdr ));
FORWARD void route_packets ARGS(( event_t *ev, ev_arg_t ev_arg ));
FORWARD int broadcast_dst ARGS(( ip_port_t *ip_port, ipaddr_t dest ));
PUBLIC int ip_read (fd, count)
int fd;
size_t count;
{
ip_fd_t *ip_fd;
acc_t *pack;
ip_fd= &ip_fd_table[fd];
if (!(ip_fd->if_flags & IFF_OPTSET))
{
return (*ip_fd->if_put_userdata)(ip_fd->if_srfd, EBADMODE,
(acc_t *)0, FALSE);
}
ip_fd->if_rd_count= count;
ip_fd->if_flags |= IFF_READ_IP;
if (ip_fd->if_rdbuf_head)
{
if (get_time() <= ip_fd->if_exp_time)
{
pack= ip_fd->if_rdbuf_head;
ip_fd->if_rdbuf_head= pack->acc_ext_link;
ip_packet2user (ip_fd, pack, ip_fd->if_exp_time,
bf_bufsize(pack));
assert(!(ip_fd->if_flags & IFF_READ_IP));
return NW_OK;
}
while (ip_fd->if_rdbuf_head)
{
pack= ip_fd->if_rdbuf_head;
ip_fd->if_rdbuf_head= pack->acc_ext_link;
bf_afree(pack);
}
}
return NW_SUSPEND;
}
PRIVATE acc_t *reassemble (ip_port, pack, pack_hdr)
ip_port_t *ip_port;
acc_t *pack;
ip_hdr_t *pack_hdr;
{
ip_ass_t *ass_ent;
size_t pack_hdr_len, pack_offset, tmp_offset;
u16_t pack_flags_fragoff;
acc_t *prev_acc, *curr_acc, *next_acc, *head_acc, *tmp_acc;
ip_hdr_t *tmp_hdr;
time_t first_time;
ass_ent= find_ass_ent (ip_port, pack_hdr->ih_id,
pack_hdr->ih_proto, pack_hdr->ih_src, pack_hdr->ih_dst);
pack_flags_fragoff= ntohs(pack_hdr->ih_flags_fragoff);
pack_hdr_len= (pack_hdr->ih_vers_ihl & IH_IHL_MASK) * 4;
pack_offset= (pack_flags_fragoff & IH_FRAGOFF_MASK)*8;
pack->acc_ext_link= NULL;
head_acc= ass_ent->ia_frags;
ass_ent->ia_frags= NULL;
if (head_acc == NULL)
{
ass_ent->ia_frags= pack;
return NULL;
}
prev_acc= NULL;
curr_acc= NULL;
next_acc= head_acc;
while(next_acc)
{
tmp_hdr= (ip_hdr_t *)ptr2acc_data(next_acc);
tmp_offset= (ntohs(tmp_hdr->ih_flags_fragoff) &
IH_FRAGOFF_MASK)*8;
if (pack_offset < tmp_offset)
break;
prev_acc= curr_acc;
curr_acc= next_acc;
next_acc= next_acc->acc_ext_link;
}
if (curr_acc == NULL)
{
assert(prev_acc == NULL);
assert(next_acc != NULL);
curr_acc= merge_frags(pack, next_acc);
head_acc= curr_acc;
}
else
{
curr_acc= merge_frags(curr_acc, pack);
if (next_acc != NULL)
curr_acc= merge_frags(curr_acc, next_acc);
if (prev_acc != NULL)
prev_acc->acc_ext_link= curr_acc;
else
head_acc= curr_acc;
}
ass_ent->ia_frags= head_acc;
pack= ass_ent->ia_frags;
pack_hdr= (ip_hdr_t *)ptr2acc_data(pack);
pack_flags_fragoff= ntohs(pack_hdr->ih_flags_fragoff);
if (!(pack_flags_fragoff & (IH_FRAGOFF_MASK|IH_MORE_FRAGS)))
/* it's now a complete packet */
{
first_time= ass_ent->ia_first_time;
ass_ent->ia_frags= 0;
ass_ent->ia_first_time= 0;
while (pack->acc_ext_link)
{
tmp_acc= pack->acc_ext_link;
pack->acc_ext_link= tmp_acc->acc_ext_link;
bf_afree(tmp_acc);
}
if ((ass_ent->ia_min_ttl) * HZ + first_time <
get_time())
{
if (broadcast_dst(ip_port, pack_hdr->ih_dst))
{
DBLOCK(1, printf(
"ip_read'reassemble: reassembly timeout for broadcast packet\n"););
bf_afree(pack); pack= NULL;
return NULL;
}
icmp_snd_time_exceeded(ip_port->ip_port, pack,
ICMP_FRAG_REASSEM);
}
else
return pack;
}
return NULL;
}
PRIVATE acc_t *merge_frags (first, second)
acc_t *first, *second;
{
ip_hdr_t *first_hdr, *second_hdr;
size_t first_hdr_size, second_hdr_size, first_datasize, second_datasize,
first_offset, second_offset;
acc_t *cut_second, *tmp_acc;
if (!second)
{
first->acc_ext_link= NULL;
return first;
}
assert (first->acc_length >= IP_MIN_HDR_SIZE);
assert (second->acc_length >= IP_MIN_HDR_SIZE);
first_hdr= (ip_hdr_t *)ptr2acc_data(first);
first_offset= (ntohs(first_hdr->ih_flags_fragoff) &
IH_FRAGOFF_MASK) * 8;
first_hdr_size= (first_hdr->ih_vers_ihl & IH_IHL_MASK) * 4;
first_datasize= ntohs(first_hdr->ih_length) - first_hdr_size;
second_hdr= (ip_hdr_t *)ptr2acc_data(second);
second_offset= (ntohs(second_hdr->ih_flags_fragoff) &
IH_FRAGOFF_MASK) * 8;
second_hdr_size= (second_hdr->ih_vers_ihl & IH_IHL_MASK) * 4;
second_datasize= ntohs(second_hdr->ih_length) - second_hdr_size;
assert (first_hdr_size + first_datasize == bf_bufsize(first));
assert (second_hdr_size + second_datasize == bf_bufsize(second));
assert (second_offset >= first_offset);
if (second_offset > first_offset+first_datasize)
{
DBLOCK(1, printf("ip fragments out of order\n"));
first->acc_ext_link= second;
return first;
}
if (second_offset + second_datasize <= first_offset +
first_datasize)
{
/* May cause problems if we try to merge. */
bf_afree(first);
return second;
}
if (!(second_hdr->ih_flags_fragoff & HTONS(IH_MORE_FRAGS)))
first_hdr->ih_flags_fragoff &= ~HTONS(IH_MORE_FRAGS);
second_datasize= second_offset+second_datasize-(first_offset+
first_datasize);
cut_second= bf_cut(second, second_hdr_size + first_offset+
first_datasize-second_offset, second_datasize);
tmp_acc= second->acc_ext_link;
bf_afree(second);
second= tmp_acc;
first_datasize += second_datasize;
first_hdr->ih_length= htons(first_hdr_size + first_datasize);
first= bf_append (first, cut_second);
first->acc_ext_link= second;
assert (first_hdr_size + first_datasize == bf_bufsize(first));
return first;
}
PRIVATE ip_ass_t *find_ass_ent (ip_port, id, proto, src, dst)
ip_port_t *ip_port;
u16_t id;
ipproto_t proto;
ipaddr_t src;
ipaddr_t dst;
{
ip_ass_t *new_ass_ent, *tmp_ass_ent;
int i;
acc_t *tmp_acc, *curr_acc;
new_ass_ent= 0;
for (i=0, tmp_ass_ent= ip_ass_table; i<IP_ASS_NR; i++,
tmp_ass_ent++)
{
if (!tmp_ass_ent->ia_frags && tmp_ass_ent->ia_first_time)
{
DBLOCK(1,
printf("strange ip_ass entry (can be a race condition)\n"));
continue;
}
if ((tmp_ass_ent->ia_srcaddr == src) &&
(tmp_ass_ent->ia_dstaddr == dst) &&
(tmp_ass_ent->ia_proto == proto) &&
(tmp_ass_ent->ia_id == id) &&
(tmp_ass_ent->ia_port == ip_port))
{
return tmp_ass_ent;
}
if (!new_ass_ent || tmp_ass_ent->ia_first_time <
new_ass_ent->ia_first_time)
{
new_ass_ent= tmp_ass_ent;
}
}
if (new_ass_ent->ia_frags)
{
DBLOCK(2, printf("old frags id= %u, proto= %u, src= ",
ntohs(new_ass_ent->ia_id),
new_ass_ent->ia_proto);
writeIpAddr(new_ass_ent->ia_srcaddr); printf(" dst= ");
writeIpAddr(new_ass_ent->ia_dstaddr); printf(": ");
ip_print_frags(new_ass_ent->ia_frags); printf("\n"));
curr_acc= new_ass_ent->ia_frags->acc_ext_link;
while (curr_acc)
{
tmp_acc= curr_acc->acc_ext_link;
bf_afree(curr_acc);
curr_acc= tmp_acc;
}
curr_acc= new_ass_ent->ia_frags;
new_ass_ent->ia_frags= 0;
if (broadcast_dst(ip_port, new_ass_ent->ia_dstaddr))
{
DBLOCK(1, printf(
"ip_read'find_ass_ent: reassembly timeout for broadcast packet\n"));
bf_afree(curr_acc); curr_acc= NULL;
}
else
{
icmp_snd_time_exceeded(ip_port->ip_port,
curr_acc, ICMP_FRAG_REASSEM);
}
}
new_ass_ent->ia_min_ttl= IP_MAX_TTL;
new_ass_ent->ia_port= ip_port;
new_ass_ent->ia_first_time= get_time();
new_ass_ent->ia_srcaddr= src;
new_ass_ent->ia_dstaddr= dst;
new_ass_ent->ia_proto= proto;
new_ass_ent->ia_id= id;
return new_ass_ent;
}
PRIVATE int ip_frag_chk(pack)
acc_t *pack;
{
ip_hdr_t *ip_hdr;
int hdr_len;
if (pack->acc_length < sizeof(ip_hdr_t))
{
DBLOCK(1, printf("wrong length\n"));
return FALSE;
}
ip_hdr= (ip_hdr_t *)ptr2acc_data(pack);
hdr_len= (ip_hdr->ih_vers_ihl & IH_IHL_MASK) * 4;
if (pack->acc_length < hdr_len)
{
DBLOCK(1, printf("wrong length\n"));
return FALSE;
}
if (((ip_hdr->ih_vers_ihl >> 4) & IH_VERSION_MASK) !=
IP_VERSION)
{
DBLOCK(1, printf("wrong version (ih_vers_ihl=0x%x)\n",
ip_hdr->ih_vers_ihl));
return FALSE;
}
if (ntohs(ip_hdr->ih_length) != bf_bufsize(pack))
{
DBLOCK(1, printf("wrong size\n"));
return FALSE;
}
if ((u16_t)~oneC_sum(0, (u16_t *)ip_hdr, hdr_len))
{
DBLOCK(1, printf("packet with wrong checksum (= %x)\n",
(u16_t)~oneC_sum(0, (u16_t *)ip_hdr, hdr_len)));
return FALSE;
}
if (hdr_len>IP_MIN_HDR_SIZE && ip_chk_hdropt((u8_t *)
(ptr2acc_data(pack) + IP_MIN_HDR_SIZE),
hdr_len-IP_MIN_HDR_SIZE))
{
DBLOCK(1, printf("packet with wrong options\n"));
return FALSE;
}
return TRUE;
}
PUBLIC void ip_packet2user (ip_fd, pack, exp_time, data_len)
ip_fd_t *ip_fd;
acc_t *pack;
time_t exp_time;
size_t data_len;
{
acc_t *tmp_pack;
ip_hdr_t *ip_hdr;
int result, ip_hdr_len;
size_t transf_size;
assert (ip_fd->if_flags & IFF_INUSE);
if (!(ip_fd->if_flags & IFF_READ_IP))
{
if (pack->acc_linkC != 1)
{
tmp_pack= bf_dupacc(pack);
bf_afree(pack);
pack= tmp_pack;
tmp_pack= NULL;
}
pack->acc_ext_link= NULL;
if (ip_fd->if_rdbuf_head == NULL)
{
ip_fd->if_rdbuf_head= pack;
ip_fd->if_exp_time= exp_time;
}
else
ip_fd->if_rdbuf_tail->acc_ext_link= pack;
ip_fd->if_rdbuf_tail= pack;
return;
}
assert (pack->acc_length >= IP_MIN_HDR_SIZE);
ip_hdr= (ip_hdr_t *)ptr2acc_data(pack);
if (ip_fd->if_ipopt.nwio_flags & NWIO_RWDATONLY)
{
ip_hdr_len= (ip_hdr->ih_vers_ihl & IH_IHL_MASK) * 4;
assert (data_len > ip_hdr_len);
data_len -= ip_hdr_len;
pack= bf_delhead(pack, ip_hdr_len);
}
if (data_len > ip_fd->if_rd_count)
{
tmp_pack= bf_cut (pack, 0, ip_fd->if_rd_count);
bf_afree(pack);
pack= tmp_pack;
transf_size= ip_fd->if_rd_count;
}
else
transf_size= data_len;
if (ip_fd->if_put_pkt)
{
(*ip_fd->if_put_pkt)(ip_fd->if_srfd, pack, transf_size);
return;
}
result= (*ip_fd->if_put_userdata)(ip_fd->if_srfd,
(size_t)0, pack, FALSE);
if (result >= 0)
{
if (data_len > transf_size)
result= EPACKSIZE;
else
result= transf_size;
}
ip_fd->if_flags &= ~IFF_READ_IP;
result= (*ip_fd->if_put_userdata)(ip_fd->if_srfd, result,
(acc_t *)0, FALSE);
assert (result >= 0);
}
PUBLIC void ip_port_arrive (ip_port, pack, ip_hdr)
ip_port_t *ip_port;
acc_t *pack;
ip_hdr_t *ip_hdr;
{
ip_fd_t *ip_fd, *first_fd, *share_fd;
unsigned long ip_pack_stat;
unsigned size;
int i;
int hash, proto;
time_t exp_time;
assert (pack->acc_linkC>0);
assert (pack->acc_length >= IP_MIN_HDR_SIZE);
if (ntohs(ip_hdr->ih_flags_fragoff) & (IH_FRAGOFF_MASK|IH_MORE_FRAGS))
{
pack= reassemble (ip_port, pack, ip_hdr);
if (!pack)
return;
assert (pack->acc_length >= IP_MIN_HDR_SIZE);
ip_hdr= (ip_hdr_t *)ptr2acc_data(pack);
assert (!(ntohs(ip_hdr->ih_flags_fragoff) &
(IH_FRAGOFF_MASK|IH_MORE_FRAGS)));
}
size= ntohs(ip_hdr->ih_length);
if (size > bf_bufsize(pack))
{
/* Should discard packet */
assert(0);
bf_afree(pack); pack= NULL;
return;
}
exp_time= get_time() + (ip_hdr->ih_ttl+1) * HZ;
if (ip_hdr->ih_dst == ip_port->ip_ipaddr)
ip_pack_stat= NWIO_EN_LOC;
else
ip_pack_stat= NWIO_EN_BROAD;
proto= ip_hdr->ih_proto;
hash= proto & (IP_PROTO_HASH_NR-1);
first_fd= NULL;
for (i= 0; i<2; i++)
{
share_fd= NULL;
ip_fd= (i == 0) ? ip_port->ip_proto_any :
ip_port->ip_proto[hash];
for (; ip_fd; ip_fd= ip_fd->if_proto_next)
{
if (i && ip_fd->if_ipopt.nwio_proto != proto)
continue;
if (!(ip_fd->if_ipopt.nwio_flags & ip_pack_stat))
continue;
if ((ip_fd->if_ipopt.nwio_flags & NWIO_REMSPEC) &&
ip_hdr->ih_src != ip_fd->if_ipopt.nwio_rem)
{
continue;
}
if ((ip_fd->if_ipopt.nwio_flags & NWIO_ACC_MASK) ==
NWIO_SHARED)
{
if (!share_fd)
{
share_fd= ip_fd;
continue;
}
if (!ip_fd->if_rdbuf_head)
share_fd= ip_fd;
continue;
}
if (!first_fd)
{
first_fd= ip_fd;
continue;
}
pack->acc_linkC++;
ip_packet2user(ip_fd, pack, exp_time, size);
}
if (share_fd)
{
pack->acc_linkC++;
ip_packet2user(share_fd, pack, exp_time, size);
}
}
if (first_fd)
{
if (first_fd->if_put_pkt &&
(first_fd->if_flags & IFF_READ_IP) &&
!(first_fd->if_ipopt.nwio_flags & NWIO_RWDATONLY))
{
(*first_fd->if_put_pkt)(first_fd->if_srfd, pack,
size);
}
else
ip_packet2user(first_fd, pack, exp_time, size);
}
else
{
if (ip_pack_stat == NWIO_EN_LOC)
{
DBLOCK(0x01,
printf("ip_port_arrive: dropping packet for proto %d\n",
proto));
}
else
{
DBLOCK(0x20, printf("dropping packet for proto %d\n",
proto));
}
bf_afree(pack);
}
}
PUBLIC void ip_arrived(ip_port, pack)
ip_port_t *ip_port;
acc_t *pack;
{
ip_hdr_t *ip_hdr;
ipaddr_t dest;
int ip_frag_len, ip_hdr_len, highbyte;
size_t pack_size;
acc_t *tmp_pack, *hdr_pack;
ev_arg_t ev_arg;
pack_size= bf_bufsize(pack);
if (pack_size < IP_MIN_HDR_SIZE)
{
DBLOCK(1, printf("wrong acc_length\n"));
bf_afree(pack);
return;
}
pack= bf_align(pack, IP_MIN_HDR_SIZE, 4);
pack= bf_packIffLess(pack, IP_MIN_HDR_SIZE);
assert (pack->acc_length >= IP_MIN_HDR_SIZE);
ip_hdr= (ip_hdr_t *)ptr2acc_data(pack);
ip_hdr_len= (ip_hdr->ih_vers_ihl & IH_IHL_MASK) << 2;
if (ip_hdr_len>IP_MIN_HDR_SIZE)
{
pack= bf_packIffLess(pack, ip_hdr_len);
ip_hdr= (ip_hdr_t *)ptr2acc_data(pack);
}
ip_frag_len= ntohs(ip_hdr->ih_length);
if (ip_frag_len != pack_size)
{
if (pack_size < ip_frag_len)
{
/* Sent ICMP? */
DBLOCK(1, printf("wrong acc_length\n"));
bf_afree(pack);
return;
}
assert(ip_frag_len<pack_size);
tmp_pack= pack;
pack= bf_cut(tmp_pack, 0, ip_frag_len);
bf_afree(tmp_pack);
pack_size= ip_frag_len;
}
if (!ip_frag_chk(pack))
{
DBLOCK(1, printf("fragment not allright\n"));
bf_afree(pack);
return;
}
/* Decide about local delivery or routing. Local delivery can happen
* when the destination is the local ip address, or one of the
* broadcast addresses and the packet happens to be delivered
* point-to-point.
*/
dest= ip_hdr->ih_dst;
if (dest == ip_port->ip_ipaddr)
{
ip_port_arrive (ip_port, pack, ip_hdr);
return;
}
if (broadcast_dst(ip_port, dest))
{
ip_port_arrive (ip_port, pack, ip_hdr);
return;
}
if (pack->acc_linkC != 1 || pack->acc_buffer->buf_linkC != 1)
{
/* Get a private copy of the IP header */
hdr_pack= bf_memreq(ip_hdr_len);
memcpy(ptr2acc_data(hdr_pack), ip_hdr, ip_hdr_len);
pack= bf_delhead(pack, ip_hdr_len);
hdr_pack->acc_next= pack;
pack= hdr_pack; hdr_pack= NULL;
ip_hdr= (ip_hdr_t *)ptr2acc_data(pack);
}
assert(pack->acc_linkC == 1);
assert(pack->acc_buffer->buf_linkC == 1);
/* Try to decrement the ttl field with one. */
if (ip_hdr->ih_ttl < 2)
{
icmp_snd_time_exceeded(ip_port->ip_port, pack,
ICMP_TTL_EXC);
return;
}
ip_hdr->ih_ttl--;
ip_hdr_chksum(ip_hdr, ip_hdr_len);
/* Avoid routing to bad destinations. */
highbyte= ntohl(dest) >> 24;
if (highbyte == 0 || highbyte == 127 ||
(highbyte == 169 && (((ntohl(dest) >> 16) & 0xff) == 254)) ||
highbyte >= 0xe0)
{
/* Bogus destination address */
bf_afree(pack);
return;
}
/* Further processing from an event handler */
if (pack->acc_linkC != 1)
{
tmp_pack= bf_dupacc(pack);
bf_afree(pack);
pack= tmp_pack;
tmp_pack= NULL;
}
pack->acc_ext_link= NULL;
if (ip_port->ip_routeq_head)
{
ip_port->ip_routeq_tail->acc_ext_link= pack;
ip_port->ip_routeq_tail= pack;
return;
}
ip_port->ip_routeq_head= pack;
ip_port->ip_routeq_tail= pack;
ev_arg.ev_ptr= ip_port;
ev_enqueue(&ip_port->ip_routeq_event, route_packets, ev_arg);
}
PUBLIC void ip_arrived_broadcast(ip_port, pack)
ip_port_t *ip_port;
acc_t *pack;
{
ip_hdr_t *ip_hdr;
int ip_frag_len, ip_hdr_len;
size_t pack_size;
acc_t *tmp_pack;
pack_size= bf_bufsize(pack);
if (pack_size < IP_MIN_HDR_SIZE)
{
DBLOCK(1, printf("wrong acc_length\n"));
bf_afree(pack);
return;
}
pack= bf_align(pack, IP_MIN_HDR_SIZE, 4);
pack= bf_packIffLess(pack, IP_MIN_HDR_SIZE);
assert (pack->acc_length >= IP_MIN_HDR_SIZE);
ip_hdr= (ip_hdr_t *)ptr2acc_data(pack);
DIFBLOCK(0x20, (ip_hdr->ih_dst & HTONL(0xf0000000)) == HTONL(0xe0000000),
printf("got multicast packet\n"));
ip_hdr_len= (ip_hdr->ih_vers_ihl & IH_IHL_MASK) << 2;
if (ip_hdr_len>IP_MIN_HDR_SIZE)
{
pack= bf_align(pack, IP_MIN_HDR_SIZE, 4);
pack= bf_packIffLess(pack, ip_hdr_len);
ip_hdr= (ip_hdr_t *)ptr2acc_data(pack);
}
ip_frag_len= ntohs(ip_hdr->ih_length);
if (ip_frag_len<pack_size)
{
tmp_pack= pack;
pack= bf_cut(tmp_pack, 0, ip_frag_len);
bf_afree(tmp_pack);
}
if (!ip_frag_chk(pack))
{
DBLOCK(1, printf("fragment not allright\n"));
bf_afree(pack);
return;
}
if (!broadcast_dst(ip_port, ip_hdr->ih_dst))
{
#if 0
printf(
"ip[%d]: broadcast packet for ip-nonbroadcast addr, src=",
ip_port->ip_port);
writeIpAddr(ip_hdr->ih_src);
printf(" dst=");
writeIpAddr(ip_hdr->ih_dst);
printf("\n");
#endif
bf_afree(pack);
return;
}
ip_port_arrive (ip_port, pack, ip_hdr);
}
PRIVATE void route_packets(ev, ev_arg)
event_t *ev;
ev_arg_t ev_arg;
{
ip_port_t *ip_port;
ipaddr_t dest;
acc_t *pack;
iroute_t *iroute;
ip_port_t *next_port;
int r, type;
ip_hdr_t *ip_hdr;
size_t req_mtu;
ip_port= ev_arg.ev_ptr;
assert(&ip_port->ip_routeq_event == ev);
while (pack= ip_port->ip_routeq_head, pack != NULL)
{
ip_port->ip_routeq_head= pack->acc_ext_link;
ip_hdr= (ip_hdr_t *)ptr2acc_data(pack);
dest= ip_hdr->ih_dst;
iroute= iroute_frag(ip_port->ip_port, dest);
if (iroute == NULL || iroute->irt_dist == IRTD_UNREACHABLE)
{
/* Also unreachable */
/* Finding out if we send a network unreachable is too
* much trouble.
*/
if (iroute == NULL)
{
printf("ip[%d]: no route to ",
ip_port-ip_port_table);
writeIpAddr(dest);
printf("\n");
}
icmp_snd_unreachable(ip_port->ip_port, pack,
ICMP_HOST_UNRCH);
continue;
}
next_port= &ip_port_table[iroute->irt_port];
if (ip_hdr->ih_flags_fragoff & HTONS(IH_DONT_FRAG))
{
req_mtu= bf_bufsize(pack);
if (req_mtu > next_port->ip_mtu ||
(iroute->irt_mtu && req_mtu>iroute->irt_mtu))
{
icmp_snd_mtu(ip_port->ip_port, pack,
next_port->ip_mtu);
continue;
}
}
if (next_port != ip_port)
{
if (iroute->irt_gateway != 0)
{
/* Just send the packet to the next gateway */
pack->acc_linkC++; /* Extra ref for ICMP */
r= next_port->ip_dev_send(next_port,
iroute->irt_gateway,
pack, IP_LT_NORMAL);
if (r == EHOSTUNREACH)
{
printf("ip[%d]: gw ",
ip_port-ip_port_table);
writeIpAddr(iroute->irt_gateway);
printf(" on ip[%d] is down for dest ",
next_port-ip_port_table);
writeIpAddr(dest);
printf("\n");
icmp_snd_unreachable(next_port-
ip_port_table, pack,
ICMP_HOST_UNRCH);
pack= NULL;
}
else
{
assert(r == 0);
bf_afree(pack); pack= NULL;
}
continue;
}
/* The packet is for the attached network. Special
* addresses are the ip address of the interface and
* net.0 if no IP_42BSD_BCAST.
*/
if (dest == next_port->ip_ipaddr)
{
ip_port_arrive (next_port, pack, ip_hdr);
continue;
}
if (dest == iroute->irt_dest)
{
/* Never forward obsolete directed broadcasts */
#if IP_42BSD_BCAST && 0
type= IP_LT_BROADCAST;
#else
/* Bogus destination address */
DBLOCK(1, printf(
"ip[%d]: dropping old-fashioned directed broadcast ",
ip_port-ip_port_table);
writeIpAddr(dest);
printf("\n"););
icmp_snd_unreachable(next_port-ip_port_table,
pack, ICMP_HOST_UNRCH);
continue;
#endif
}
else if (dest == (iroute->irt_dest |
~iroute->irt_subnetmask))
{
if (!ip_forward_directed_bcast)
{
/* Do not forward directed broadcasts */
DBLOCK(1, printf(
"ip[%d]: dropping directed broadcast ",
ip_port-ip_port_table);
writeIpAddr(dest);
printf("\n"););
icmp_snd_unreachable(next_port-
ip_port_table, pack,
ICMP_HOST_UNRCH);
continue;
}
else
type= IP_LT_BROADCAST;
}
else
type= IP_LT_NORMAL;
/* Just send the packet to it's destination */
pack->acc_linkC++; /* Extra ref for ICMP */
r= next_port->ip_dev_send(next_port, dest, pack, type);
if (r == EHOSTUNREACH)
{
DBLOCK(1, printf("ip[%d]: next hop ",
ip_port-ip_port_table);
writeIpAddr(dest);
printf(" on ip[%d] is down\n",
next_port-ip_port_table););
icmp_snd_unreachable(next_port-ip_port_table,
pack, ICMP_HOST_UNRCH);
pack= NULL;
}
else
{
assert(r == 0 || (printf("r = %d\n", r), 0));
bf_afree(pack); pack= NULL;
}
continue;
}
/* Now we know that the packet should be routed over the same
* network as it came from. If there is a next hop gateway,
* we can send the packet to that gateway and send a redirect
* ICMP to the sender if the sender is on the attached
* network. If there is no gateway complain.
*/
if (iroute->irt_gateway == 0)
{
printf("ip_arrived: packet should not be here, src=");
writeIpAddr(ip_hdr->ih_src);
printf(" dst=");
writeIpAddr(ip_hdr->ih_dst);
printf("\n");
bf_afree(pack);
continue;
}
if (((ip_hdr->ih_src ^ ip_port->ip_ipaddr) &
ip_port->ip_subnetmask) == 0)
{
/* Finding out if we can send a network redirect
* instead of a host redirect is too much trouble.
*/
pack->acc_linkC++;
icmp_snd_redirect(ip_port->ip_port, pack,
ICMP_REDIRECT_HOST, iroute->irt_gateway);
}
else
{
printf("ip_arrived: packet is wrongly routed, src=");
writeIpAddr(ip_hdr->ih_src);
printf(" dst=");
writeIpAddr(ip_hdr->ih_dst);
printf("\n");
printf("in port %d, output %d, dest net ",
ip_port->ip_port,
iroute->irt_port);
writeIpAddr(iroute->irt_dest);
printf("/");
writeIpAddr(iroute->irt_subnetmask);
printf(" next hop ");
writeIpAddr(iroute->irt_gateway);
printf("\n");
bf_afree(pack);
continue;
}
/* No code for unreachable ICMPs here. The sender should
* process the ICMP redirect and figure it out.
*/
ip_port->ip_dev_send(ip_port, iroute->irt_gateway, pack,
IP_LT_NORMAL);
}
}
PRIVATE int broadcast_dst(ip_port, dest)
ip_port_t *ip_port;
ipaddr_t dest;
{
ipaddr_t my_ipaddr, netmask, classmask;
/* Treat class D (multicast) address as broadcasts. */
if ((dest & HTONL(0xF0000000)) == HTONL(0xE0000000))
{
return 1;
}
/* Accept without complaint if netmask not yet configured. */
if (!(ip_port->ip_flags & IPF_NETMASKSET))
{
return 1;
}
/* Two possibilities, 0 (iff IP_42BSD_BCAST) and -1 */
if (dest == HTONL((ipaddr_t)-1))
return 1;
#if IP_42BSD_BCAST
if (dest == HTONL((ipaddr_t)0))
return 1;
#endif
netmask= ip_port->ip_subnetmask;
my_ipaddr= ip_port->ip_ipaddr;
if (((my_ipaddr ^ dest) & netmask) != 0)
{
classmask= ip_port->ip_classfulmask;
/* Not a subnet broadcast, maybe a classful broadcast */
if (((my_ipaddr ^ dest) & classmask) != 0)
{
return 0;
}
/* Two possibilities, net.0 (iff IP_42BSD_BCAST) and net.-1 */
if ((dest & ~classmask) == ~classmask)
{
return 1;
}
#if IP_42BSD_BCAST
if ((dest & ~classmask) == 0)
return 1;
#endif
return 0;
}
if (!(ip_port->ip_flags & IPF_SUBNET_BCAST))
return 0; /* No subnet broadcasts on this network */
/* Two possibilities, subnet.0 (iff IP_42BSD_BCAST) and subnet.-1 */
if ((dest & ~netmask) == ~netmask)
return 1;
#if IP_42BSD_BCAST
if ((dest & ~netmask) == 0)
return 1;
#endif
return 0;
}
void ip_process_loopb(ev, arg)
event_t *ev;
ev_arg_t arg;
{
ip_port_t *ip_port;
acc_t *pack;
ip_port= arg.ev_ptr;
assert(ev == &ip_port->ip_loopb_event);
while(pack= ip_port->ip_loopb_head, pack != NULL)
{
ip_port->ip_loopb_head= pack->acc_ext_link;
ip_arrived(ip_port, pack);
}
}
/*
* $PchId: ip_read.c,v 1.33 2005/06/28 14:18:50 philip Exp $
*/
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