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Remove one unnecessary copy in csp_send_direct per call #27

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Remove one unnecessary copy in csp_send_direct per call #27

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136 changes: 61 additions & 75 deletions src/csp_io.c
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Original file line number Diff line number Diff line change
Expand Up @@ -91,8 +91,8 @@ void csp_send_direct(csp_id_t* idout, csp_packet_t * packet, csp_iface_t * route
/* Try to find the destination on any local subnets */
int via = CSP_NO_VIA_ADDRESS;
csp_iface_t * iface = NULL;
csp_iface_t * next_iface = NULL;
csp_packet_t * copy = NULL;
int local_found = 0;

/* Quickly send on loopback */
if(idout->dst == csp_if_lo.addr){
Expand All @@ -103,117 +103,103 @@ void csp_send_direct(csp_id_t* idout, csp_packet_t * packet, csp_iface_t * route
/* Make copy as broadcast modifies destination making iflist_get_by_subnet the skip next redundant ifaces */
csp_id_t _idout = *idout;

while ((iface = csp_iflist_get_by_subnet(idout->dst, iface)) != NULL) {

local_found = 1;
#define CONTINUE_IF_SAME_SUBNET(snd_iface) \
/* Do not send back to same inteface (split horizon) */ \
/* This check is is similar to that below, but faster */ \
if (snd_iface == routed_from) { \
continue; \
} \
\
/* Do not send to interface with similar subnet (split horizon) */ \
if (csp_iflist_is_within_subnet(snd_iface->addr, routed_from)) { \
continue; \
}

/* Do not send back to same inteface (split horizon)
* This check is is similar to that below, but faster */
if (iface == routed_from) {
continue;
}
#define SEND_PACKET(snd_iface, snd_pkt) \
/* Apply outgoing interface address to packet */ \
if ((from_me) && (idout->src == 0)) { \
_idout.src = snd_iface->addr; \
} \
\
if (snd_pkt != NULL) { \
csp_send_direct_iface(&_idout, snd_pkt, snd_iface, via, from_me); \
} \

#define SEND_PACKET_CHECK_BROADCAST(snd_iface, snd_pkt) \
/* Rewrite routed brodcast (L3) to local (L2) when arriving at the */ \
/*interface */ \
if (csp_id_is_broadcast(idout->dst, snd_iface)) { \
_idout.dst = csp_id_get_max_nodeid(); \
} \
SEND_PACKET(snd_iface, snd_pkt);

/* Do not send to interface with similar subnet (split horizon) */
if (csp_iflist_is_within_subnet(iface->addr, routed_from)) {
continue;
}
while ((iface = csp_iflist_get_by_subnet(idout->dst, iface)) != NULL) {

/* Apply outgoing interface address to packet */
if ((from_me) && (idout->src == 0)) {
_idout.src = iface->addr;
}
CONTINUE_IF_SAME_SUBNET(iface);

/* Rewrite routed brodcast (L3) to local (L2) when arriving at the interface */
if (csp_id_is_broadcast(idout->dst, iface)) {
_idout.dst = csp_id_get_max_nodeid();
}

/* Todo: Find an elegant way to avoid making a copy when only a single destination interface
* is found. But without looping the list twice. And without using stack memory.
* Is this even possible? */
copy = csp_buffer_clone(packet);
if (copy != NULL) {
csp_send_direct_iface(&_idout, copy, iface, via, from_me);
// TODO Mark likely / unlikely depending on frequency of multiple
if (next_iface != NULL) {
copy = csp_buffer_clone(packet);
SEND_PACKET_CHECK_BROADCAST(next_iface, copy);
}

next_iface = iface;
}

/* If the above worked, we don't want to look at the routing table */
if (local_found == 1) {
csp_buffer_free(packet);
if (next_iface != NULL) {
SEND_PACKET_CHECK_BROADCAST(next_iface, packet);
return;
}

#undef SEND_PACKET_CHECK_BROADCAST

#if CSP_USE_RTABLE
/* Try to send via routing table */
int route_found = 0;
csp_route_t * route = csp_rtable_find_route(idout->dst);
if (route != NULL) {
do {
route_found = 1;

/* Do not send back to same inteface (split horizon)
* This check is is similar to that below, but faster */
if (route->iface == routed_from) {
continue;
}
CONTINUE_IF_SAME_SUBNET(route->iface);

/* Do not send to interface with similar subnet (split horizon) */
if (csp_iflist_is_within_subnet(route->iface->addr, routed_from)) {
continue;
}

/* Apply outgoing interface address to packet */
if ((from_me) && (idout->src == 0)) {
idout->src = route->iface->addr;
}

copy = csp_buffer_clone(packet);
if (copy != NULL) {
csp_send_direct_iface(idout, copy, route->iface, route->via, from_me);
// TODO Mark likely / unlikely depending on frequency of multiple
if (next_iface != NULL) {
copy = csp_buffer_clone(packet);
SEND_PACKET(next_iface, copy);
}
next_iface = route->iface;
via = route->via;
} while ((route = csp_rtable_search_backward(route)) != NULL);
}

/* If the above worked, we don't want to look at default interfaces */
if (route_found == 1) {
csp_buffer_free(packet);
if (next_iface != NULL) {
SEND_PACKET(next_iface, packet);
return;
}

#endif

/* Try to send via default interfaces */
while ((iface = csp_iflist_get_by_isdfl(iface)) != NULL) {

/* Do not send back to same inteface (split horizon)
* This check is is similar to that below, but faster */
if (iface == routed_from) {
continue;
}

/* Do not send to interface with similar subnet (split horizon) */
if (csp_iflist_is_within_subnet(iface->addr, routed_from)) {
continue;
}

/* Apply outgoing interface address to packet */
if ((from_me) && (idout->src == 0)) {
idout->src = iface->addr;
}
CONTINUE_IF_SAME_SUBNET(iface);

/* Todo: Find an elegant way to avoid making a copy when only a single destination interface
* is found. But without looping the list twice. And without using stack memory.
* Is this even possible? */
copy = csp_buffer_clone(packet);
if (copy != NULL) {
csp_send_direct_iface(idout, copy, iface, via, from_me);
// TODO Mark likely / unlikely depending on frequency of multiple
if (next_iface != NULL) {
copy = csp_buffer_clone(packet);
SEND_PACKET(next_iface, copy);
}
next_iface = iface;
}

if (next_iface != NULL) {
SEND_PACKET(next_iface, packet);
return;
}

csp_buffer_free(packet);

#undef CONTINUE_IF_SAME_SUBNET
#undef SEND_PACKET
}

__weak void csp_output_hook(csp_id_t * idout, csp_packet_t * packet, csp_iface_t * iface, uint16_t via, int from_me) {
Expand Down