ubgpsuite/lonetix/bgp/parameters.c

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2021-06-07 16:55:13 +02:00
// SPDX-License-Identifier: LGPL-3.0-or-later
/**
* \file bgp/parameters.c
*
* Deals with BGP OPEN parameters.
*
* \copyright The DoubleFourteen Code Forge (C) All Rights Reserved
* \author Lorenzo Cogotti
*/
#include "bgp/bgp_local.h"
Judgement Bgp_StartMsgParms(Bgpparmiter *it, Bgpmsg *msg)
{
const Bgpopen *open = Bgp_GetMsgOpen(msg);
if (!open)
return NG; // error already set
Bgp_StartParms(it, BGP_OPENPARMS(open));
return OK; // error already cleared
}
void Bgp_StartParms(Bgpparmiter *it, const Bgpparmseg *p)
{
it->ptr = (Uint8 *) p->parms;
it->base = it->ptr;
it->lim = it->base + p->len;
}
Bgpparm *Bgp_NextParm(Bgpparmiter *it)
{
if (it->ptr >= it->lim) {
Bgp_SetErrStat(BGPENOERR);
return NULL;
}
Bgpparm *p = (Bgpparm *) it->ptr;
size_t left = it->lim - it->ptr;
if (left < 2uLL || left < 2uLL + p->len) {
Bgp_SetErrStat(BGPETRUNCMSG);
return NULL;
}
it->ptr += 2 + p->len;
Bgp_SetErrStat(BGPENOERR);
return p;
}
Judgement Bgp_StartMsgCaps(Bgpcapiter *it, Bgpmsg *msg)
{
if (Bgp_StartMsgParms(&it->pi, msg) != OK)
return NG; // error already set
// Set starting point so Bgp_NextCap() scans for next parameter
it->base = it->lim = it->ptr = it->pi.ptr;
return OK;
}
void Bgp_StartCaps(Bgpcapiter *it, const Bgpparmseg *parms)
{
Bgp_StartParms(&it->pi, parms);
// Set starting point so Bgp_NextCap() scans for next parameter
it->base = it->lim = it->ptr = it->pi.ptr;
}
Bgpcap *Bgp_NextCap(Bgpcapiter *it)
{
if (it->ptr >= it->lim) {
// Try to find another CAPABILITY parameter
Bgpparm *p;
while ((p = Bgp_NextParm(&it->pi)) != NULL) {
if (p->code == BGP_PARM_CAPABILITY)
break;
}
if (!p) {
// Scanned all parameters, nothing found
Bgp_SetErrStat(BGPENOERR);
return NULL;
}
// Setup for reading new capabilities from `p`
it->base = (Uint8 *) p + 2;
it->lim = it->base + p->len;
it->ptr = it->base;
}
// Return current capability and move over
size_t left = it->lim - it->ptr;
Bgpcap *cap = (Bgpcap *) it->ptr;
if (left < 2uLL || left < 2uLL + cap->len) {
Bgp_SetErrStat(BGPETRUNCMSG);
return NULL;
}
it->ptr += 2 + cap->len;
Bgp_SetErrStat(BGPENOERR);
return cap;
}