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d1bb637cba
set for broadcast frames).
298 lines
9.0 KiB
C
298 lines
9.0 KiB
C
/*
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Serval Distributed Numbering Architecture (DNA)
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Copyright (C) 2010 Paul Gardner-Stephen
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#include "serval.h"
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int overlay_payload_verify(overlay_frame *p)
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{
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/* Make sure that an incoming payload has a valid signature from the sender.
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This is used to prevent spoofing */
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return WHY("function not implemented");
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}
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int op_append_type(overlay_buffer *headers,overlay_frame *p)
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{
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unsigned char c[3];
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switch(p->type&OF_TYPE_FLAG_BITS)
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{
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case OF_TYPE_FLAG_NORMAL:
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c[0]=p->type|p->modifiers;
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if (debug&DEBUG_PACKETFORMATS) fprintf(stderr,"type resolves to %02x\n",c[0]);
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if (ob_append_bytes(headers,c,1)) return -1;
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break;
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case OF_TYPE_FLAG_E12:
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c[0]=(p->type&OF_MODIFIER_BITS)|OF_TYPE_EXTENDED12;
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c[1]=(p->type>>4)&0xff;
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if (debug&DEBUG_PACKETFORMATS) fprintf(stderr,"type resolves to %02x%02x\n",c[0],c[1]);
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if (ob_append_bytes(headers,c,2)) return -1;
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break;
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case OF_TYPE_FLAG_E20:
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c[0]=(p->type&OF_MODIFIER_BITS)|OF_TYPE_EXTENDED20;
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c[1]=(p->type>>4)&0xff;
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c[2]=(p->type>>12)&0xff;
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if (debug&DEBUG_PACKETFORMATS) fprintf(stderr,"type resolves to %02x%02x%02x\n",c[0],c[1],c[2]);
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if (ob_append_bytes(headers,c,3)) return -1;
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break;
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default:
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/* Don't know this type of frame */
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WHY("Asked for format frame with unknown TYPE_FLAG bits");
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return -1;
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}
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return 0;
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}
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int overlay_frame_package_fmt1(overlay_frame *p,overlay_buffer *b)
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{
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/* Convert a payload (frame) structure into a series of bytes.
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Assumes that any encryption etc has already been done.
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Will pick a next hop if one has not been chosen.
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*/
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int nexthoplen=0;
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overlay_buffer *headers=ob_new(256);
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if (!headers) return WHY("could not allocate overlay buffer for headers");
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if (!p) return WHY("p is NULL");
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if (!b) return WHY("b is NULL");
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/* Build header */
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int fail=0;
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if (p->nexthop_address_status!=OA_RESOLVED) {
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dump("destination",(unsigned char *)p->destination,32);
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if (overlay_address_is_broadcast(p->destination)) {
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/* Broadcast frames are broadcast rather than unicast to next hop.
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Just check if the broadcast frame should be dropped first. */
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if (overlay_broadcast_drop_check(p->destination))
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return WHY("This broadcast packet ID has been seen recently");
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int i;
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for(i=0;i<SID_SIZE;i++) p->nexthop[i]=0xff;
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p->nexthop_address_status=OA_RESOLVED;
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} else {
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if (overlay_get_nexthop((unsigned char *)p->destination,p->nexthop,&nexthoplen,&p->nexthop_interface)) {
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fail++;
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return WHY("could not determine next hop address for payload");
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}
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else p->nexthop_address_status=OA_RESOLVED;
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}
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}
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if (p->source[0]<0x10) {
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// Make sure that addresses do not overload the special address spaces of 0x00*-0x0f*
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fail++;
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return WHY("packet source address begins with reserved value 0x00-0x0f");
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}
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if (p->destination[0]<0x10) {
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// Make sure that addresses do not overload the special address spaces of 0x00*-0x0f*
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fail++;
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return WHY("packet destination address begins with reserved value 0x00-0x0f");
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}
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if (p->nexthop[0]<0x10) {
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// Make sure that addresses do not overload the special address spaces of 0x00*-0x0f*
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fail++;
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return WHY("packet nexthop address begins with reserved value 0x00-0x0f");
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}
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/* Write fields into binary structure in correct order */
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/* Write out type field byte(s) */
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if (!fail) if (op_append_type(headers,p)) fail++;
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/* Write out TTL */
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if (!fail) if (ob_append_byte(headers,p->ttl)) fail++;
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/* Length. This is the fun part, because we cannot calculate how many bytes we need until
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we have abbreviated the addresses, and the length encoding we use varies according to the
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length encoded. The simple option of running the abbreviations twice won't work because
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we rely on context for abbreviating the addresses. So we write it initially and then patch it
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after.
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*/
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if (!fail) {
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int max_len=((SID_SIZE+3)*3+headers->length+p->payload->length);
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ob_append_rfs(headers,max_len);
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int addrs_start=headers->length;
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/* Write out addresses as abbreviated as possible */
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overlay_abbreviate_append_address(headers,p->nexthop);
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overlay_abbreviate_set_most_recent_address(p->nexthop);
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overlay_abbreviate_append_address(headers,p->destination);
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overlay_abbreviate_set_most_recent_address(p->destination);
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overlay_abbreviate_append_address(headers,p->source);
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overlay_abbreviate_set_most_recent_address(p->source);
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int addrs_len=headers->length-addrs_start;
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int actual_len=addrs_len+p->payload->length;
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ob_patch_rfs(headers,actual_len);
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}
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if (fail) {
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ob_free(headers);
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return WHY("failure count was non-zero");
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}
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/* Write payload format plus total length of header bits */
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if (ob_makespace(b,2+headers->length+p->payload->length)) {
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/* Not enough space free in output buffer */
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ob_free(headers);
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if (debug&DEBUG_PACKETFORMATS)
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WHY("Could not make enough space free in output buffer");
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return -1;
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}
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/* Package up headers and payload */
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ob_checkpoint(b);
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if (ob_append_bytes(b,headers->bytes,headers->length))
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{ fail++; WHY("could not append header"); }
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if (ob_append_bytes(b,p->payload->bytes,p->payload->length))
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{ fail++; WHY("could not append payload"); }
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/* XXX SIGN &/or ENCRYPT */
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ob_free(headers);
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if (fail) { ob_rewind(b); return WHY("failure count was non-zero"); } else return 0;
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}
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overlay_buffer *overlay_payload_unpackage(overlay_frame *b) {
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/* Extract the payload at the current location in the buffer. */
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WHY("not implemented");
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return NULL;
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}
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int dump_queue(char *msg,int q)
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{
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overlay_txqueue *qq=&overlay_tx[q];
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printf("Contents of TX queue #%d (%s):\n",q,msg);
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printf(" length=%d, maxLength=%d\n",qq->length,qq->maxLength);
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struct overlay_frame *f=qq->first,*l=qq->last;
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printf(" head of queue = %p, tail of queue = %p\n",
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f,l);
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struct overlay_frame *n=f;
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int count=0;
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while(n) {
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printf(" queue entry #%d : prev=%p, next=%p\n",
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count,n->prev,n->next);
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if (n==n->next) {
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printf(" ERROR: loop in queue\n");
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return -1;
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}
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n=n->next;
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}
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return 0;
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}
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int overlay_payload_enqueue(int q,overlay_frame *p)
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{
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/* Add payload p to queue q.
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Queues get scanned from first to last, so we should append new entries
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on the end of the queue.
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Complain if there are too many frames in the queue.
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*/
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if (q<0||q>=OQ_MAX) return WHY("Invalid queue specified");
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if (!p) return WHY("Cannot queue NULL");
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if (overlay_tx[q].length>=overlay_tx[q].maxLength) return WHY("Queue congested");
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dump_queue("before",q);
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overlay_frame *l=overlay_tx[q].last;
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if (l) l->next=p;
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p->prev=l;
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p->next=NULL;
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p->enqueued_at=overlay_gettime_ms();
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overlay_tx[q].last=p;
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if (!overlay_tx[q].first) overlay_tx[q].first=p;
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overlay_tx[q].length++;
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dump_queue("after",q);
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return 0;
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}
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int op_free(overlay_frame *p)
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{
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if (!p) return WHY("Asked to free NULL");
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if (p->prev&&p->prev->next==p) return WHY("p->prev->next still points here");
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if (p->next&&p->next->prev==p) return WHY("p->next->prev still points here");
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p->prev=NULL;
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p->next=NULL;
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if (p->payload) ob_free(p->payload);
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p->payload=NULL;
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free(p);
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return 0;
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}
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int overlay_frame_set_neighbour_as_source(overlay_frame *f,overlay_neighbour *n)
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{
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if (!n) return WHY("Neighbour was null");
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bcopy(n->node->sid,f->source,SID_SIZE);
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f->source_address_status=OA_RESOLVED;
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return 0;
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}
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int overlay_frame_set_neighbour_as_destination(overlay_frame *f,overlay_neighbour *n)
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{
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if (!n) return WHY("Neighbour was null");
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bcopy(n->node->sid,f->destination,SID_SIZE);
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f->destination_address_status=OA_RESOLVED;
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return 0;
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}
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int overlay_frame_set_broadcast_as_destination(overlay_frame *f)
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{
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overlay_broadcast_generate_address(f->destination);
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f->destination_address_status=OA_RESOLVED;
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return 0;
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}
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unsigned char *overlay_get_my_sid()
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{
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/* Make sure we can find our SID */
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int zero=0;
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if (!findHlr(hlr,&zero,NULL,NULL)) { WHY("Could not find first entry in HLR"); return NULL; }
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return &hlr[zero+4];
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}
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int overlay_frame_set_me_as_source(overlay_frame *f)
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{
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unsigned char *sid=overlay_get_my_sid();
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if (!sid) return WHY("overlay_get_my_sid() failed.");
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bcopy(sid,f->source,SID_SIZE);
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f->source_address_status=OA_RESOLVED;
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return 0;
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}
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