From 394acced118df7360e480920c65ca260c5b8c44f Mon Sep 17 00:00:00 2001
From: Ondrej Filip <feela@network.cz>
Date: Sun, 2 Apr 2000 20:41:33 +0000
Subject: Work on lsupdates continues. Some checksum cleanup.

---
 proto/ospf/dbdes.c  |  3 +-
 proto/ospf/lsalib.c | 87 ++++++++++++++++++++++++++++++++---------------------
 proto/ospf/lsalib.h |  2 ++
 proto/ospf/lsupd.c  | 26 +++++++++++++---
 proto/ospf/packet.c |  1 +
 5 files changed, 78 insertions(+), 41 deletions(-)

diff --git a/proto/ospf/dbdes.c b/proto/ospf/dbdes.c
index ee2f96f9..c6aba363 100644
--- a/proto/ospf/dbdes.c
+++ b/proto/ospf/dbdes.c
@@ -189,11 +189,10 @@ ospf_dbdes_reqladd(struct ospf_dbdes_packet *ps, struct proto *p,
   for(i=0;i<j;i++)
   {
     ntohlsah(plsa+i, &lsa);
-    /* FIXME Test Checksum */
     if(((he=ospf_hash_find(gr,lsa.id,lsa.rt,lsa.type))==NULL)||
       (lsa_comp(&lsa, &(he->lsa))==1))
     {
-      /* Is this confition necessary? */
+      /* Is this condition necessary? */
       if(ospf_hash_find(n->lsrqh,lsa.id,lsa.rt,lsa.type)==NULL)
       {
         sn=ospf_hash_get(n->lsrqh,lsa.id,lsa.rt,lsa.type);
diff --git a/proto/ospf/lsalib.c b/proto/ospf/lsalib.c
index 72ca55c3..a7ef8040 100644
--- a/proto/ospf/lsalib.c
+++ b/proto/ospf/lsalib.c
@@ -230,62 +230,79 @@ ntohlsab(void *n, void *h, u8 type, u16 len)
 #define LSA_CHECKSUM_OFFSET    15
 
 /* FIXME This is VERY uneficient, I have huge endianity problems */
-
 void
 lsasum_calculate(struct ospf_lsa_header *h,void *body,struct proto_ospf *po)
+{
+  u16 length;
+  
+  length=h->length;
+
+  htonlsah(h,h);
+  htonlsab(body,body,h->type,length);
+
+  (void)lsasum_check(h,body,po);
+  
+  ntohlsah(h,h);
+  ntohlsab(body,body,h->type,length);
+}
+
+/*
+ * Note, that this function expects that LSA is in big endianity
+ * It also returns value in big endian
+ */
+u16
+lsasum_check(struct ospf_lsa_header *h,void *body,struct proto_ospf *po)
 {
   u8 *sp, *ep, *p, *q, *b;
   int c0 = 0, c1 = 0;
   int x, y;
-  u16 length;
+  u16 length,chsum;
 
-  h->checksum = 0;
   b=body;
-  length = h->length-2;
   sp = (char *) &h->options;
-
-  htonlsah(h,h);
-  htonlsab(b,b,h->type,length+2);
+  length=ntohs(h->length)-2;
+  h->checksum = 0;
 
   for (ep = sp + length; sp < ep; sp = q)
+  {		/* Actually MODX is very large, do we need the for-cyclus? */
+    q = sp + MODX;
+    if (q > ep) q = ep;
+    for (p = sp; p < q; p++)
     {
-      q = sp + MODX;
-      if (q > ep)
-        q = ep;
-      for (p = sp; p < q; p++)
-        {
-          if(p<(u8 *)(h+1))
-	  {
-            c0 += *p;
-	    /*DBG("XXXXXX: %u\t%u\n", p-sp, *p);*/
-	  }
-	  else
-          {
-            c0 += *(b+(p-sp)-sizeof(struct ospf_lsa_header)+2);
-	    /*DBG("YYYYYY: %u\t%u\n", p-sp,*(b+(p-sp)-sizeof(struct ospf_lsa_header)+2));*/
-          }
-          c1 += c0;
-        }
-      c0 %= 255;
-      c1 %= 255;
+      /* 
+       * I count with bytes from header and than from body
+       * but if there is no body, it's appended to header
+       * (probably checksum in update receiving) and I go on
+       * after header
+       */
+      if((b==NULL) || (p<(u8 *)(h+1)))
+      {
+	      c0 += *p;
+      }
+      else
+      {
+	      c0 += *(b+(p-sp)-sizeof(struct ospf_lsa_header)+2);
+      }
+
+      c1 += c0;
     }
+    c0 %= 255;
+    c1 %= 255;
+  }
 
   x = ((length - LSA_CHECKSUM_OFFSET) * c0 - c1) % 255;
-  if (x <= 0)
-    x += 255;
+  if (x <= 0) x += 255;
   y = 510 - c0 - x;
-  if (y > 255)
-    y -= 255;
+  if (y > 255) y -= 255;
 
-  h->checksum = x + (y << 8);
-  
-  ntohlsah(h,h);
-  ntohlsab(b,b,h->type,length+2);
+  chsum= x + (y << 8);
+  h->checksum = chsum;
+  return chsum;
 }
 
 int
 lsa_comp(struct ospf_lsa_header *l1, struct ospf_lsa_header *l2)
-			/* Return codes form view of l1 */
+			/* Return codes from point of view of l1 */
 {
   if(l1->sn<l2->sn) return CMP_NEWER;
     if(l1->sn==l2->sn)
diff --git a/proto/ospf/lsalib.h b/proto/ospf/lsalib.h
index b6547c76..5332d2ef 100644
--- a/proto/ospf/lsalib.h
+++ b/proto/ospf/lsalib.h
@@ -16,6 +16,8 @@ void htonlsab(void *h, void *n, u8 type, u16 len);
 void ntohlsab(void *n, void *h, u8 type, u16 len);
 void lsasum_calculate(struct ospf_lsa_header *header, void *body,
   struct proto_ospf *p);
+u16 lsasum_check(struct ospf_lsa_header *h,void *body,struct proto_ospf *po);
+
 #define CMP_NEWER 1
 #define CMP_SAME 0
 #define CMP_OLDER -1
diff --git a/proto/ospf/lsupd.c b/proto/ospf/lsupd.c
index 8f9d6aa9..2fa01378 100644
--- a/proto/ospf/lsupd.c
+++ b/proto/ospf/lsupd.c
@@ -83,10 +83,10 @@ void
 ospf_lsupd_rx(struct ospf_lsupd_packet *ps, struct proto *p,
   struct ospf_iface *ifa, u16 size)
 {
-  u32 nrid, myrid;
+  u32 area,nrid,myrid;
   struct ospf_neighbor *n;
-  struct ospf_lsreq_header *lsh;
-  int length;
+  struct ospf_lsa_header *lsa;
+  u16 length;
   u8 i;
 
   nrid=ntohl(ps->ospf_packet.routerid);
@@ -99,6 +99,24 @@ ospf_lsupd_rx(struct ospf_lsupd_packet *ps, struct proto *p,
       nrid);
     return ;
   }
-  /* FIXME Go on! */
+  if(n->state<NEIGHBOR_EXCHANGE)
+  {
+    debug("%s: Received lsupd in lesser state than EXCHANGE from (%u)\n",
+      p->name);
+    return;
+  }
+
+  lsa=(struct ospf_lsa_header *)(ps+1);
+  area=htonl(ps->ospf_packet.areaid);
+  for(i=0;i<ntohl(ps->lsano);i++)
+  {
+    if(lsa->checksum==lsasum_check(lsa,NULL,(struct proto_ospf *)p))
+    {
+      DBG("Processing update Type: %u ID: %u RT: %u\n",lsa->type,
+        ntohl(lsa->id), ntohl(lsa->rt));
+      /* FIXME Go on */
+    }
+    lsa=(struct ospf_lsa_header *)(((u8 *)lsa)+ntohs(lsa->length));
+  }
 }
 
diff --git a/proto/ospf/packet.c b/proto/ospf/packet.c
index a176c44e..8cc308a0 100644
--- a/proto/ospf/packet.c
+++ b/proto/ospf/packet.c
@@ -145,6 +145,7 @@ ospf_rx_hook(sock *sk, int size)
       break;
     case LSUPD:
       DBG("%s: Link state update received.\n", p->name);
+      ospf_lsupd_rx((struct ospf_lsupd_packet *)ps, p, ifa, size);
       break;
     case LSACK:
       DBG("%s: Link state ack received.\n", p->name);
-- 
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