serval-dna/overlay_payload.c
2013-05-29 11:58:05 +09:30

185 lines
5.6 KiB
C

/*
Serval Distributed Numbering Architecture (DNA)
Copyright (C) 2010 Paul Gardner-Stephen
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include "serval.h"
#include "conf.h"
#include "str.h"
#include "overlay_buffer.h"
#include "overlay_packet.h"
static int overlay_frame_build_header(int packet_version, struct decode_context *context,
struct overlay_buffer *buff,
int queue, int type, int modifiers, int ttl, int sequence,
struct broadcast *broadcast, struct subscriber *next_hop,
struct subscriber *destination, struct subscriber *source)
{
if (ttl < 0 || ttl > PAYLOAD_TTL_MAX)
return WHYF("invalid ttl=%d", ttl);
int flags = modifiers & (PAYLOAD_FLAG_CIPHERED | PAYLOAD_FLAG_SIGNED);
if (ttl==1 && !broadcast)
flags |= PAYLOAD_FLAG_ONE_HOP;
if (destination && destination==next_hop)
flags |= PAYLOAD_FLAG_ONE_HOP;
if (source == context->sender)
flags |= PAYLOAD_FLAG_SENDER_SAME;
if (!destination)
flags |= PAYLOAD_FLAG_TO_BROADCAST;
if (type!=OF_TYPE_DATA)
flags |= PAYLOAD_FLAG_LEGACY_TYPE;
if (ob_append_byte(buff, flags)) return -1;
if (!(flags & PAYLOAD_FLAG_SENDER_SAME)){
if (overlay_address_append(context, buff, source)) return -1;
}
if (flags & PAYLOAD_FLAG_TO_BROADCAST){
if (!(flags & PAYLOAD_FLAG_ONE_HOP)){
if (overlay_broadcast_append(buff, broadcast)) return -1;
}
}else{
if (overlay_address_append(context, buff, destination)) return -1;
if (!(flags & PAYLOAD_FLAG_ONE_HOP)){
if (overlay_address_append(context, buff, next_hop)) return -1;
}
}
if (!(flags & PAYLOAD_FLAG_ONE_HOP)){
if (ob_append_byte(buff, ttl | ((queue&3)<<5))) return -1;
}
if (flags & PAYLOAD_FLAG_LEGACY_TYPE){
if (ob_append_byte(buff, type)) return -1;
}
if (packet_version>0)
if (ob_append_byte(buff, sequence))
return -1;
return 0;
}
int overlay_frame_append_payload(struct decode_context *context, overlay_interface *interface,
struct overlay_frame *p, struct overlay_buffer *b)
{
/* Convert a payload (frame) structure into a series of bytes.
Assumes that any encryption etc has already been done.
Will pick a next hop if one has not been chosen.
*/
ob_checkpoint(b);
if (config.debug.packetconstruction){
DEBUGF( "+++++\nFrame from %s to %s of type 0x%02x %s:",
alloca_tohex_sid(p->source->sid),
alloca_tohex_sid(p->destination->sid),p->type,
"append_payload stuffing into packet");
if (p->payload)
dump("payload contents", &p->payload->bytes[0],p->payload->position);
}
struct broadcast *broadcast=NULL;
if ((!p->destination) && !is_all_matching(p->broadcast_id.id,BROADCAST_LEN,0)){
broadcast = &p->broadcast_id;
}
if (overlay_frame_build_header(p->packet_version, context, b,
p->queue, p->type, p->modifiers, p->ttl, p->mdp_sequence&0xFF,
broadcast, p->next_hop,
p->destination, p->source))
goto cleanup;
if (ob_append_ui16(b, ob_position(p->payload)))
goto cleanup;
if (ob_append_bytes(b, ob_ptr(p->payload), ob_position(p->payload))) {
WHY("could not append payload");
goto cleanup;
}
return 0;
cleanup:
ob_rewind(b);
return -1;
}
int single_packet_encapsulation(struct overlay_buffer *b, struct overlay_frame *frame){
overlay_interface *interface=frame->interface;
int interface_number = interface - overlay_interfaces;
struct decode_context context;
bzero(&context, sizeof(struct decode_context));
if (frame->source_full)
my_subscriber->send_full=1;
int seq = interface->sequence_number++;
if (overlay_packet_init_header(frame->packet_version, ENCAP_SINGLE, &context, b, NULL, 0, interface_number, seq))
return WHY("Failed to init header");
struct broadcast *broadcast=NULL;
if ((!frame->destination) && !is_all_matching(frame->broadcast_id.id,BROADCAST_LEN,0))
broadcast = &frame->broadcast_id;
if (overlay_frame_build_header(frame->packet_version, &context, b,
frame->queue, frame->type,
frame->modifiers, frame->ttl, frame->mdp_sequence & 0xFF,
broadcast, frame->next_hop,
frame->destination, frame->source))
return WHY("Failed to build header");
if (ob_append_buffer(b, frame->payload))
return WHY("Failed to append payload");
return 0;
}
int op_free(struct overlay_frame *p)
{
if (!p) return WHY("Asked to free NULL");
if (p->prev&&p->prev->next==p) return WHY("p->prev->next still points here");
if (p->next&&p->next->prev==p) return WHY("p->next->prev still points here");
p->prev=NULL;
p->next=NULL;
if (p->payload) ob_free(p->payload);
p->payload=NULL;
free(p);
return 0;
}
struct overlay_frame *op_dup(struct overlay_frame *in)
{
if (!in) return NULL;
/* clone the frame */
struct overlay_frame *out=malloc(sizeof(struct overlay_frame));
if (!out) { WHY("malloc() failed"); return NULL; }
/* copy main data structure */
bcopy(in,out,sizeof(struct overlay_frame));
if (in->payload)
out->payload=ob_dup(in->payload);
return out;
}