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New payload header format

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This commit is contained in:
Jeremy Lakeman 2012-11-26 14:52:49 +10:30
parent 5a5853f38a
commit f13db5405e
4 changed files with 103 additions and 93 deletions
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16
constants.h
View File

@ -87,7 +87,6 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
#define OVERLAY_MAX_LOCAL_IDENTITIES 256
/* Overlay mesh packet codes */
#define OF_TYPE_BITS 0xf0
#define OF_TYPE_SELFANNOUNCE 0x10 /* BATMAN style announcement frames */
#define OF_TYPE_SELFANNOUNCE_ACK 0x20 /* BATMAN style "I saw your announcment" frames */
#define OF_TYPE_DATA 0x30 /* Ordinary data frame.
@ -101,16 +100,17 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
#define OF_TYPE_PLEASEEXPLAIN 0x60 /* Request for resolution of an abbreviated address */
#define OF_TYPE_NODEANNOUNCE 0x70
/* Modifiers that indicate the disposition of the frame */
#define OF_MODIFIER_BITS 0x0f
#define PAYLOAD_FLAG_SENDER_SAME (1<<0)
#define PAYLOAD_FLAG_TO_BROADCAST (1<<1)
#define PAYLOAD_FLAG_ONE_HOP (1<<2)
#define PAYLOAD_FLAG_LONG_PAYLOAD (1<<3)
#define PAYLOAD_FLAG_CIPHERED (1<<4)
#define PAYLOAD_FLAG_SIGNED (1<<5)
/* Crypto/security options */
#define OF_CRYPTO_NONE 0x00
#define OF_CRYPTO_CIPHERED 0x04 /* Encrypted frame */
#define OF_CRYPTO_SIGNED 0x08 /* signed frame */
/* QOS packet queue bits */
#define OF_QUEUE_BITS 0x03
#define OF_CRYPTO_CIPHERED PAYLOAD_FLAG_CIPHERED /* Encrypted frame */
#define OF_CRYPTO_SIGNED PAYLOAD_FLAG_SIGNED /* signed frame */
/* Keep track of last 32 observations of a node.
Hopefully this is enough, if not, we will increase.

6
overlay_address.c
View File

@ -546,11 +546,11 @@ int send_please_explain(struct decode_context *context, struct subscriber *sourc
else
context->please_explain->source = my_subscriber;
if (destination){
if (destination && destination->reachable!=REACHABLE_NONE){
context->please_explain->destination = destination;
context->please_explain->ttl=64;
}else{
context->please_explain->ttl=2;// how will this work with olsr??
context->please_explain->ttl=1;// how will this work with olsr??
overlay_broadcast_generate_address(&context->please_explain->broadcast_id);
}
@ -559,7 +559,7 @@ int send_please_explain(struct decode_context *context, struct subscriber *sourc
if (!overlay_payload_enqueue(context->please_explain))
RETURN(0);
op_free(context->please_explain);
RETURN(0);
RETURN(-1);
}
// process an incoming request for explanation of subscriber abbreviations

129
overlay_packetformats.c
View File

@ -176,9 +176,6 @@ int packetOkOverlay(struct overlay_interface *interface,unsigned char *packet, s
struct decode_context context;
bzero(&context, sizeof context);
if (len<HEADERFIELDS_LEN)
return WHY("Packet is too short");
time_ms_t now = gettime_ms();
struct overlay_buffer *b = ob_static(packet, len);
ob_limitsize(b, len);
@ -213,49 +210,74 @@ int packetOkOverlay(struct overlay_interface *interface,unsigned char *packet, s
while(b->position < b->sizeLimit){
context.invalid_addresses=0;
int flags = ob_get(b);
/* Get normal form of packet type and modifiers */
f.type=flags&OF_TYPE_BITS;
f.modifiers=flags&OF_MODIFIER_BITS;
f.queue = (f.modifiers & OF_QUEUE_BITS) +1;
/* Get time to live */
f.ttl=ob_get(b);
f.ttl--;
/* Decode length of remainder of frame */
int payload_len=ob_get_ui16(b);
if (payload_len <=0)
/* we fell off the end of the packet? */
break;
dump("decoding header", b->bytes + b->position, payload_len);
int next_payload = b->position + payload_len;
/* Always attempt to resolve all of the addresses in a packet, or we could fail to understand an important payload
eg, peer sends two payloads travelling in opposite directions;
[Next, Dest, Sender] forwarding a payload we just send, so Sender == Me
[Next, Dest, Sender] delivering a payload to us so Next == Me
But Next would be encoded as OA_CODE_PREVIOUS, so we must parse all three addresses,
even if Next is obviously not intended for us
*/
struct subscriber *nexthop=NULL;
bzero(f.broadcast_id.id, BROADCAST_LEN);
int process=1;
int forward=1;
int flags = ob_get(b);
// if the structure of the addresses looks wrong, stop immediately
if (overlay_address_parse(&context, b, &f.broadcast_id, &nexthop)
|| overlay_address_parse(&context, b, NULL, &f.destination)
|| overlay_address_parse(&context, b, NULL, &f.source)){
break;
if (flags & PAYLOAD_FLAG_SENDER_SAME){
f.source = context.sender;
}else{
if (overlay_address_parse(&context, b, NULL, &f.source))
break;
if (!f.source || f.source->reachable==REACHABLE_SELF)
process=forward=0;
}
if (flags & PAYLOAD_FLAG_TO_BROADCAST){
if (!(flags & PAYLOAD_FLAG_ONE_HOP)){
if (overlay_address_parse(&context, b, &f.broadcast_id, NULL))
break;
if (overlay_broadcast_drop_check(&f.broadcast_id)){
process=forward=0;
if (debug&DEBUG_OVERLAYFRAMES)
DEBUGF("Ignoring duplicate broadcast (%s)", alloca_tohex(f.broadcast_id.id, BROADCAST_LEN));
}
}
f.destination=NULL;
}else{
if (overlay_address_parse(&context, b, NULL, &f.destination))
break;
if (!f.destination || f.destination->reachable!=REACHABLE_SELF){
process=0;
}
if (!(flags & PAYLOAD_FLAG_ONE_HOP)){
if (overlay_address_parse(&context, b, NULL, &nexthop))
break;
if (!nexthop || nexthop->reachable!=REACHABLE_SELF){
forward=0;
}
}
}
if (flags & PAYLOAD_FLAG_ONE_HOP){
f.ttl=1;
}else{
int ttl_qos = ob_get(b);
f.ttl = ttl_qos & 0x1F;
f.queue = (ttl_qos >> 5) & 3;
}
f.ttl--;
if (f.ttl<=0)
forward=0;
f.type=ob_get(b);
if (f.type<0)
break;
f.modifiers=flags;
// TODO allow for one byte length
int payload_len = ob_get_ui16(b);
if (payload_len <=0)
break;
int next_payload = b->position + payload_len;
// if we can't understand one of the addresses, skip processing the payload
if (context.invalid_addresses)
goto next;
@ -270,26 +292,8 @@ int packetOkOverlay(struct overlay_interface *interface,unsigned char *packet, s
DEBUGF("Next hop %s", alloca_tohex_sid(nexthop->sid));
}
// ignore any payload we sent
if (f.source->reachable==REACHABLE_SELF){
if (debug&DEBUG_OVERLAYFRAMES)
DEBUGF("Ignoring payload from myself (%s)", alloca_tohex_sid(f.source->sid));
if (!process && !forward)
goto next;
}
// skip unicast payloads that aren't for me
if (nexthop && nexthop->reachable!=REACHABLE_SELF){
if (debug&DEBUG_OVERLAYFRAMES)
DEBUGF("Ignoring payload that is not meant for me (%s)", alloca_tohex_sid(nexthop->sid));
goto next;
}
// skip broadcast payloads we've already seen
if ((!nexthop) && overlay_broadcast_drop_check(&f.broadcast_id)){
if (debug&DEBUG_OVERLAYFRAMES)
DEBUGF("Ignoring duplicate broadcast (%s)", alloca_tohex(f.broadcast_id.id, BROADCAST_LEN));
goto next;
}
f.payload = ob_slice(b, b->position, next_payload - b->position);
if (!f.payload){
@ -300,13 +304,12 @@ int packetOkOverlay(struct overlay_interface *interface,unsigned char *packet, s
ob_limitsize(f.payload, next_payload - b->position);
// forward payloads that are for someone else or everyone
if ((!f.destination) ||
(f.destination->reachable != REACHABLE_SELF && f.destination->reachable != REACHABLE_NONE)){
if (forward){
overlay_forward_payload(&f);
}
// process payloads that are for me or everyone
if ((!f.destination) || f.destination->reachable==REACHABLE_SELF){
if (process){
process_incoming_frame(now, interface, &f, &context);
}

45
overlay_payload.c
View File

@ -27,35 +27,42 @@ int overlay_frame_build_header(struct decode_context *context, struct overlay_bu
struct broadcast *broadcast, struct subscriber *next_hop,
struct subscriber *destination, struct subscriber *source){
int x = buff->position;
int flags = modifiers & (PAYLOAD_FLAG_CIPHERED | PAYLOAD_FLAG_SIGNED);
int q_bits = queue;
if (q_bits>0) q_bits--;
if (q_bits>3) q_bits=3;
int type_byte = type|modifiers|q_bits;
if (ttl==1 && !broadcast)
flags |= PAYLOAD_FLAG_ONE_HOP;
if (destination && destination==next_hop)
flags |= PAYLOAD_FLAG_ONE_HOP;
if (ttl>64)
ttl=64;
if (source == context->sender)
flags |= PAYLOAD_FLAG_SENDER_SAME;
if (ob_append_byte(buff, type_byte)) return -1;
if (ob_append_byte(buff, ttl)) return -1;
if (ob_append_rfs(buff, 2)) return -1;
if (!destination)
flags |= PAYLOAD_FLAG_TO_BROADCAST;
if (broadcast){
if (overlay_broadcast_append(context, buff, broadcast)) return -1;
}else{
if (overlay_address_append(context, buff, next_hop)) return -1;
if (ob_append_byte(buff, flags)) return -1;
if (!(flags & PAYLOAD_FLAG_SENDER_SAME)){
if (overlay_address_append(context, buff, source)) return -1;
}
if (destination){
if (flags & PAYLOAD_FLAG_TO_BROADCAST){
if (!(flags & PAYLOAD_FLAG_ONE_HOP)){
if (overlay_broadcast_append(context, buff, broadcast)) return -1;
}
}else{
if (overlay_address_append(context, buff, destination)) return -1;
}else{
if (ob_append_byte(buff, OA_CODE_PREVIOUS)) return -1;
if (!(flags & PAYLOAD_FLAG_ONE_HOP)){
if (overlay_address_append(context, buff, next_hop)) return -1;
}
}
if (overlay_address_append(context, buff, source)) return -1;
if (!(flags & PAYLOAD_FLAG_ONE_HOP)){
if (ob_append_byte(buff, ttl | ((queue&3)<<5))) return -1;
}
if (ob_append_byte(buff, type)) return -1;
dump("written header", buff->bytes + x, buff->position - x);
if (ob_append_rfs(buff, 2)) return -1;
return 0;
}