[*] Initial commit

tools/bgpgrep/bgpgrep_vmfunc.c

@@ -0,0 +1,215 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+/**
+ * \file bgpgrep_vmfunc.c
+ *
+ * `bgpgrep`-specific BGP VM extended functions
+ *
+ * \copyright The DoubleFourteen Code Forge (C) All Rights Reserved
+ * \author    Lorenzo Cogotti
+ */
+
+#include "bgpgrep_local.h"
+
+#include "bgp/vmintrin.h"
+
+#include <assert.h>
+#include <string.h>
+
+typedef struct Asnnode Asnnode;
+struct Asnnode {
+	Asn32    asn;
+	Sint32   pos;
+	Asnnode *children[2];
+};
+
+typedef struct Asntree Asntree;
+struct Asntree {
+	Uint32   n;
+	Asnnode *root;
+};
+
+// NOTE: Need this macro so we can safely Bgp_VmTempFree() a bunch of
+//       nodes with a single call, instead of using a loop
+#define ALIGNEDNODESIZ ALIGN(sizeof(Asnnode), ALIGNMENT)
+
+Asnnode *GetAsnTreeNode(Bgpvm *vm, Asntree *t, Asn32 asn)
+{
+	Asnnode **p, *i;
+
+	// Search suitable spot inside tree
+	p = &t->root;
+	while ((i = *p) != NULL && asn != i->asn)
+		p = &i->children[asn > i->asn];
+
+	if (!i) {
+		// No node with this ASN
+		i = (Asnnode *) Bgp_VmTempAlloc(vm, ALIGNEDNODESIZ);
+		if (!i)
+			return NULL;
+
+		i->asn = asn;
+		i->pos = -1;
+		i->children[0] = i->children[1] = NULL;
+
+		*p = i;
+
+		t->n++;
+	}
+	return i;
+}
+
+void BgpgrepF_PeerAddrMatch(Bgpvm *vm)
+{
+	/*
+	 * POPS:
+	 * -1 - Peerlistop *
+	 *
+	 * PUSHES:
+	 * TRUE if S.peerAddr and S.peerAs match peer list, FALSE otherwise
+	 */
+	if (!BGP_VMCHKSTKSIZ(vm, 1))
+		return;
+
+	Boolean foundPeer = FALSE;  // unless found otherwise
+	for (Peerlistop *i = (Peerlistop *) BGP_VMPOPA(vm); i; i = i->next) {
+		switch (i->opc) {
+		default:
+		case PEER_ADDR_NOP:
+			break;
+		case PEER_ADDR_EQ:
+			if (!Ip_Equal(&i->addr, &S.peerAddr)) continue;
+
+			break;
+		case PEER_ADDR_NE:
+			if (Ip_Equal(&i->addr, &S.peerAddr)) continue;
+
+			break;
+		}
+		if (i->asn == ASN_ANY)
+			foundPeer = TRUE;
+		else if (ISASNNOT(i->asn))
+			foundPeer = ASN(i->asn) != ASN(S.peerAs);
+		else
+			foundPeer = ASN(i->asn) == ASN(S.peerAs);
+
+		if (foundPeer)
+			break;
+	}
+
+	// XXX: include match info
+
+	BGP_VMPUSH(vm, foundPeer);
+}
+
+FORCE_INLINE int TIMESTAMP_CMP(const Timestampop *stamp)
+{
+	int res = (S.timestampSecs > stamp->secs) - (S.timestampSecs < stamp->secs);
+	if (res == 0)
+		res = (S.timestampMicrosecs > stamp->microsecs) -
+		      (S.timestampMicrosecs < stamp->microsecs);
+
+	return res;
+}
+
+void BgpgrepF_TimestampCompare(Bgpvm *vm)
+{
+	/*
+	 * POPS:
+	 * -1 - Timestampop *
+	 *
+	 * PUSHES:
+	 * TRUE if S.timestampSecs and S.timestampMicrosecs matches argument,
+	 * FALSE otherwise
+	 */
+	if (!BGP_VMCHKSTKSIZ(vm, 1))
+		return;
+
+	Boolean res = FALSE;
+
+	Timestampop *stamp = (Timestampop *) BGP_VMPOPA(vm);
+	if (!stamp)  // should never happen
+		goto nomatch;
+
+	switch (stamp->opc) {
+	case TIMESTAMP_LE:
+		res = (TIMESTAMP_CMP(stamp) <= 0);
+		break;
+	case TIMESTAMP_LT:
+		res = (TIMESTAMP_CMP(stamp) <  0);
+		break;
+	case TIMESTAMP_NE:
+		res = (TIMESTAMP_CMP(stamp) != 0);
+		break;
+	case TIMESTAMP_EQ:
+		res = (TIMESTAMP_CMP(stamp) == 0);
+		break;
+	case TIMESTAMP_GT:
+		res = (TIMESTAMP_CMP(stamp) >  0);
+		break;
+	case TIMESTAMP_GE:
+		res = (TIMESTAMP_CMP(stamp) >= 0);
+		break;
+	default:
+		UNREACHABLE;
+		return;
+	}
+
+nomatch:
+
+	// XXX: include match info
+	BGP_VMPUSH(vm, res);
+}
+
+void BgpgrepF_FindAsLoops(Bgpvm *vm)
+{
+	/* POPS:
+	 * NONE
+	 *
+	 * PUSHES:
+	 * TRUE if loops are found inside AS PATH, FALSE otherwise
+	 */
+	Aspathiter it;
+
+	Asntree t;
+	Asn     asn;
+
+	Sint32  pos = 0;
+	Boolean foundLoop = FALSE;
+
+	if (Bgp_StartMsgRealAsPath(&it, vm->msg) != OK)
+		goto nomatch;
+
+	memset(&t, 0, sizeof(t));
+	while ((asn = Bgp_NextAsPath(&it)) != -1) {
+		Asn32 as32 = ASN(asn);
+		if (as32 == AS4_TRANS) {
+			// AS_TRANS are irrelevant for loops
+			pos++;
+			continue;
+		}
+
+		Asnnode *n = GetAsnTreeNode(vm, &t, as32);
+		if (!n)
+			return;  // out of temporary memory
+
+		if (n->pos != -1 && n->pos < pos - 1) {
+			foundLoop = TRUE;
+			break;
+		}
+
+		n->pos = pos++;  // record last position of this ASN and move on
+	}
+	if (Bgp_GetErrStat(NULL)) {
+		vm->errCode = BGPEVMMSGERR;
+		return;
+	}
+
+	Bgp_VmTempFree(vm, t.n * ALIGNEDNODESIZ);
+
+nomatch:
+
+	// XXX: include match info
+	if (BGP_VMCHKSTK(vm, 1))
+		BGP_VMPUSH(vm, foundLoop);
+}