Add InMon's sFlow Agent library to the build system.

The C source and header files added in this commit is covered under the
InMon sFlow license at http://www.inmon.com/technology/sflowlicense.txt

The library requires -Wno-unused to compile without warnings, so this
commit adds that for building the sFlow code only.  Automake can only
change compiler flags on a per-library or per-program basis, so sFlow
is built as a separate library.

The library will be used in upcoming commits.

1 files changed, 832 insertions, 0 deletions

diff --git a/lib/sflow_receiver.c b/lib/sflow_receiver.c
new file mode 100644
index 00000000..7fccab30
--- /dev/null
+++ b/lib/sflow_receiver.c
@@ -0,0 +1,832 @@
+/* Copyright (c) 2002-2009 InMon Corp. Licensed under the terms of the InMon sFlow licence: */
+/* http://www.inmon.com/technology/sflowlicense.txt */
+
+#include <assert.h>
+#include "sflow_api.h"
+
+static void resetSampleCollector(SFLReceiver *receiver);
+static void sendSample(SFLReceiver *receiver);
+static void sflError(SFLReceiver *receiver, char *errm);
+inline static void putNet32(SFLReceiver *receiver, u_int32_t val);
+inline static void putAddress(SFLReceiver *receiver, SFLAddress *addr);
+#ifdef SFLOW_DO_SOCKET
+static void initSocket(SFLReceiver *receiver);
+#endif
+
+/*_________________--------------------------__________________
+  _________________    sfl_receiver_init     __________________
+  -----------------__________________________------------------
+*/
+
+void sfl_receiver_init(SFLReceiver *receiver, SFLAgent *agent)
+{
+    /* first clear everything */
+    memset(receiver, 0, sizeof(*receiver));
+
+    /* now copy in the parameters */
+    receiver->agent = agent;
+
+    /* set defaults */
+    receiver->sFlowRcvrMaximumDatagramSize = SFL_DEFAULT_DATAGRAM_SIZE;
+    receiver->sFlowRcvrPort = SFL_DEFAULT_COLLECTOR_PORT;
+
+#ifdef SFLOW_DO_SOCKET
+    /* initialize the socket address */
+    initSocket(receiver);
+#endif
+
+    /* preset some of the header fields */
+    receiver->sampleCollector.datap = receiver->sampleCollector.data;
+    putNet32(receiver, SFLDATAGRAM_VERSION5);
+    putAddress(receiver, &agent->myIP);
+    putNet32(receiver, agent->subId);
+
+    /* prepare to receive the first sample */
+    resetSampleCollector(receiver);
+}
+
+/*_________________---------------------------__________________
+  _________________      reset                __________________
+  -----------------___________________________------------------
+
+  called on timeout, or when owner string is cleared
+*/
+
+static void reset(SFLReceiver *receiver) {
+    // ask agent to tell samplers and pollers to stop sending samples
+    sfl_agent_resetReceiver(receiver->agent, receiver);
+    // reinitialize
+    sfl_receiver_init(receiver, receiver->agent);
+}
+
+#ifdef SFLOW_DO_SOCKET
+/*_________________---------------------------__________________
+  _________________      initSocket           __________________
+  -----------------___________________________------------------
+*/
+
+static void initSocket(SFLReceiver *receiver) {
+    if(receiver->sFlowRcvrAddress.type == SFLADDRESSTYPE_IP_V6) {
+	struct sockaddr_in6 *sa6 = &receiver->receiver6;
+	sa6->sin6_port = htons((u_int16_t)receiver->sFlowRcvrPort);
+	sa6->sin6_family = AF_INET6;
+	sa6->sin6_addr = receiver->sFlowRcvrAddress.address.ip_v6;
+    }
+    else {
+	struct sockaddr_in *sa4 = &receiver->receiver4;
+	sa4->sin_port = htons((u_int16_t)receiver->sFlowRcvrPort);
+	sa4->sin_family = AF_INET;
+	sa4->sin_addr = receiver->sFlowRcvrAddress.address.ip_v4;
+    }
+}
+#endif
+
+/*_________________----------------------------------------_____________
+  _________________          MIB Vars                      _____________
+  -----------------________________________________________-------------
+*/
+
+char * sfl_receiver_get_sFlowRcvrOwner(SFLReceiver *receiver) {
+    return receiver->sFlowRcvrOwner;
+}
+void sfl_receiver_set_sFlowRcvrOwner(SFLReceiver *receiver, char *sFlowRcvrOwner) {
+    receiver->sFlowRcvrOwner = sFlowRcvrOwner;
+    if(sFlowRcvrOwner == NULL || sFlowRcvrOwner[0] == '\0') {
+	// reset condition! owner string was cleared
+	reset(receiver);
+    }
+}
+time_t sfl_receiver_get_sFlowRcvrTimeout(SFLReceiver *receiver) {
+    return receiver->sFlowRcvrTimeout;
+}
+void sfl_receiver_set_sFlowRcvrTimeout(SFLReceiver *receiver, time_t sFlowRcvrTimeout) {
+    receiver->sFlowRcvrTimeout =sFlowRcvrTimeout;
+} 
+u_int32_t sfl_receiver_get_sFlowRcvrMaximumDatagramSize(SFLReceiver *receiver) {
+    return receiver->sFlowRcvrMaximumDatagramSize;
+}
+void sfl_receiver_set_sFlowRcvrMaximumDatagramSize(SFLReceiver *receiver, u_int32_t sFlowRcvrMaximumDatagramSize) {
+    u_int32_t mdz = sFlowRcvrMaximumDatagramSize;
+    if(mdz < SFL_MIN_DATAGRAM_SIZE) mdz = SFL_MIN_DATAGRAM_SIZE;
+    receiver->sFlowRcvrMaximumDatagramSize = mdz;
+}
+SFLAddress *sfl_receiver_get_sFlowRcvrAddress(SFLReceiver *receiver) {
+    return &receiver->sFlowRcvrAddress;
+}
+void sfl_receiver_set_sFlowRcvrAddress(SFLReceiver *receiver, SFLAddress *sFlowRcvrAddress) {
+    if(sFlowRcvrAddress) receiver->sFlowRcvrAddress = *sFlowRcvrAddress; // structure copy
+#ifdef SFLOW_DO_SOCKET
+    initSocket(receiver);
+#endif
+}
+u_int32_t sfl_receiver_get_sFlowRcvrPort(SFLReceiver *receiver) {
+    return receiver->sFlowRcvrPort;
+}
+void sfl_receiver_set_sFlowRcvrPort(SFLReceiver *receiver, u_int32_t sFlowRcvrPort) {
+    receiver->sFlowRcvrPort = sFlowRcvrPort;
+    // update the socket structure
+#ifdef SFLOW_DO_SOCKET
+    initSocket(receiver);
+#endif
+}
+
+/*_________________---------------------------__________________
+  _________________   sfl_receiver_tick       __________________
+  -----------------___________________________------------------
+*/
+
+void sfl_receiver_tick(SFLReceiver *receiver, time_t now)
+{
+    // if there are any samples to send, flush them now
+    if(receiver->sampleCollector.numSamples > 0) sendSample(receiver);
+    // check the timeout
+    if(receiver->sFlowRcvrTimeout && (u_int32_t)receiver->sFlowRcvrTimeout != 0xFFFFFFFF) {
+	// count down one tick and reset if we reach 0
+	if(--receiver->sFlowRcvrTimeout == 0) reset(receiver);
+    }
+}
+
+/*_________________-----------------------------__________________
+  _________________   receiver write utilities  __________________
+  -----------------_____________________________------------------
+*/
+ 
+inline static void put32(SFLReceiver *receiver, u_int32_t val)
+{
+    *receiver->sampleCollector.datap++ = val;
+}
+
+inline static void putNet32(SFLReceiver *receiver, u_int32_t val)
+{
+    *receiver->sampleCollector.datap++ = htonl(val);
+}
+
+inline static void putNet32_run(SFLReceiver *receiver, void *obj, size_t quads)
+{
+    u_int32_t *from = (u_int32_t *)obj;
+    while(quads--) putNet32(receiver, *from++);
+}
+
+inline static void putNet64(SFLReceiver *receiver, u_int64_t val64)
+{
+    u_int32_t *firstQuadPtr = receiver->sampleCollector.datap;
+    // first copy the bytes in
+    memcpy((u_char *)firstQuadPtr, &val64, 8);
+    if(htonl(1) != 1) {
+	// swap the bytes, and reverse the quads too
+	u_int32_t tmp = *receiver->sampleCollector.datap++;
+	*firstQuadPtr = htonl(*receiver->sampleCollector.datap);
+	*receiver->sampleCollector.datap++ = htonl(tmp);
+    }
+    else receiver->sampleCollector.datap += 2;
+}
+
+inline static void put128(SFLReceiver *receiver, u_char *val)
+{
+    memcpy(receiver->sampleCollector.datap, val, 16);
+    receiver->sampleCollector.datap += 4;
+}
+
+inline static void putString(SFLReceiver *receiver, SFLString *s)
+{
+    putNet32(receiver, s->len);
+    memcpy(receiver->sampleCollector.datap, s->str, s->len);
+    receiver->sampleCollector.datap += (s->len + 3) / 4; /* pad to 4-byte boundary */
+}
+
+inline static u_int32_t stringEncodingLength(SFLString *s) {
+    // answer in bytes,  so remember to mulitply by 4 after rounding up to nearest 4-byte boundary
+    return 4 + (((s->len + 3) / 4) * 4);
+}
+
+inline static void putAddress(SFLReceiver *receiver, SFLAddress *addr)
+{
+    // encode unspecified addresses as IPV4:0.0.0.0 - or should we flag this as an error?
+    if(addr->type == 0) {
+	putNet32(receiver, SFLADDRESSTYPE_IP_V4);
+	put32(receiver, 0);
+    }
+    else {
+	putNet32(receiver, addr->type);
+	if(addr->type == SFLADDRESSTYPE_IP_V4) put32(receiver, addr->address.ip_v4.addr);
+	else put128(receiver, addr->address.ip_v6.addr);
+    }
+}
+
+inline static u_int32_t addressEncodingLength(SFLAddress *addr) {
+    return (addr->type == SFLADDRESSTYPE_IP_V6) ? 20 : 8;  // type + address (unspecified == IPV4)
+}
+
+inline static void putMACAddress(SFLReceiver *receiver, u_int8_t *mac)
+{
+    memcpy(receiver->sampleCollector.datap, mac, 6);
+    receiver->sampleCollector.datap += 2;
+}
+
+inline static void putSwitch(SFLReceiver *receiver, SFLExtended_switch *sw)
+{
+    putNet32(receiver, sw->src_vlan);
+    putNet32(receiver, sw->src_priority);
+    putNet32(receiver, sw->dst_vlan);
+    putNet32(receiver, sw->dst_priority);
+}
+
+inline static void putRouter(SFLReceiver *receiver, SFLExtended_router *router)
+{
+    putAddress(receiver, &router->nexthop);
+    putNet32(receiver, router->src_mask);
+    putNet32(receiver, router->dst_mask);
+}
+
+inline static u_int32_t routerEncodingLength(SFLExtended_router *router) {
+    return addressEncodingLength(&router->nexthop) + 8;
+}
+
+inline static void putGateway(SFLReceiver *receiver, SFLExtended_gateway *gw)
+{
+    putAddress(receiver, &gw->nexthop);
+    putNet32(receiver, gw->as);
+    putNet32(receiver, gw->src_as);
+    putNet32(receiver, gw->src_peer_as);
+    putNet32(receiver, gw->dst_as_path_segments);
+    {
+	u_int32_t seg = 0;
+	for(; seg < gw->dst_as_path_segments; seg++) {
+	    putNet32(receiver, gw->dst_as_path[seg].type);
+	    putNet32(receiver, gw->dst_as_path[seg].length);
+	    putNet32_run(receiver, gw->dst_as_path[seg].as.seq, gw->dst_as_path[seg].length);
+	}
+    }
+    putNet32(receiver, gw->communities_length);
+    putNet32_run(receiver, gw->communities, gw->communities_length);
+    putNet32(receiver, gw->localpref);
+}
+
+inline static u_int32_t gatewayEncodingLength(SFLExtended_gateway *gw) {
+    u_int32_t elemSiz = addressEncodingLength(&gw->nexthop);
+    u_int32_t seg = 0;
+    elemSiz += 16; // as, src_as, src_peer_as, dst_as_path_segments 
+    for(; seg < gw->dst_as_path_segments; seg++) {
+	elemSiz += 8; // type, length 
+	elemSiz += 4 * gw->dst_as_path[seg].length; // set/seq bytes
+    }
+    elemSiz += 4; // communities_length
+    elemSiz += 4 * gw->communities_length; // communities
+    elemSiz += 4; // localpref
+    return elemSiz;
+}
+
+inline static void putUser(SFLReceiver *receiver, SFLExtended_user *user)
+{
+    putNet32(receiver, user->src_charset);
+    putString(receiver, &user->src_user);
+    putNet32(receiver, user->dst_charset);
+    putString(receiver, &user->dst_user);
+}
+
+inline static u_int32_t userEncodingLength(SFLExtended_user *user) {
+    return 4
+	+ stringEncodingLength(&user->src_user)
+	+ 4
+	+ stringEncodingLength(&user->dst_user);
+}
+
+inline static void putUrl(SFLReceiver *receiver, SFLExtended_url *url)
+{
+    putNet32(receiver, url->direction);
+    putString(receiver, &url->url);
+    putString(receiver, &url->host);
+}
+
+inline static u_int32_t urlEncodingLength(SFLExtended_url *url) {
+    return 4
+	+ stringEncodingLength(&url->url)
+	+ stringEncodingLength(&url->host);
+}
+
+inline static void putLabelStack(SFLReceiver *receiver, SFLLabelStack *labelStack)
+{
+    putNet32(receiver, labelStack->depth);
+    putNet32_run(receiver, labelStack->stack, labelStack->depth);
+}
+
+inline static u_int32_t labelStackEncodingLength(SFLLabelStack *labelStack) {
+    return 4 + (4 * labelStack->depth);
+}
+
+inline static void putMpls(SFLReceiver *receiver, SFLExtended_mpls *mpls)
+{
+    putAddress(receiver, &mpls->nextHop);
+    putLabelStack(receiver, &mpls->in_stack);
+    putLabelStack(receiver, &mpls->out_stack);
+}
+
+inline static u_int32_t mplsEncodingLength(SFLExtended_mpls *mpls) {
+    return addressEncodingLength(&mpls->nextHop)
+	+ labelStackEncodingLength(&mpls->in_stack)
+	+ labelStackEncodingLength(&mpls->out_stack);
+}
+
+inline static void putNat(SFLReceiver *receiver, SFLExtended_nat *nat)
+{
+    putAddress(receiver, &nat->src);
+    putAddress(receiver, &nat->dst);
+}
+
+inline static u_int32_t natEncodingLength(SFLExtended_nat *nat) {
+    return addressEncodingLength(&nat->src)
+	+ addressEncodingLength(&nat->dst);
+}
+
+inline static void putMplsTunnel(SFLReceiver *receiver, SFLExtended_mpls_tunnel *tunnel)
+{
+    putString(receiver, &tunnel->tunnel_lsp_name);
+    putNet32(receiver, tunnel->tunnel_id);
+    putNet32(receiver, tunnel->tunnel_cos);
+}
+
+inline static u_int32_t mplsTunnelEncodingLength(SFLExtended_mpls_tunnel *tunnel) {
+    return stringEncodingLength(&tunnel->tunnel_lsp_name) + 8;
+}
+
+inline static void putMplsVc(SFLReceiver *receiver, SFLExtended_mpls_vc *vc)
+{
+    putString(receiver, &vc->vc_instance_name);
+    putNet32(receiver, vc->vll_vc_id);
+    putNet32(receiver, vc->vc_label_cos);
+}
+
+inline static u_int32_t mplsVcEncodingLength(SFLExtended_mpls_vc *vc) {
+    return stringEncodingLength( &vc->vc_instance_name) + 8;
+}
+
+inline static void putMplsFtn(SFLReceiver *receiver, SFLExtended_mpls_FTN *ftn)
+{
+    putString(receiver, &ftn->mplsFTNDescr);
+    putNet32(receiver, ftn->mplsFTNMask);
+}
+
+inline static u_int32_t mplsFtnEncodingLength(SFLExtended_mpls_FTN *ftn) {
+    return stringEncodingLength( &ftn->mplsFTNDescr) + 4;
+}
+
+inline static void putMplsLdpFec(SFLReceiver *receiver, SFLExtended_mpls_LDP_FEC *ldpfec)
+{
+    putNet32(receiver, ldpfec->mplsFecAddrPrefixLength);
+}
+
+inline static u_int32_t mplsLdpFecEncodingLength(SFLExtended_mpls_LDP_FEC *ldpfec) {
+    return 4;
+}
+
+inline static void putVlanTunnel(SFLReceiver *receiver, SFLExtended_vlan_tunnel *vlanTunnel)
+{
+    putLabelStack(receiver, &vlanTunnel->stack);
+}
+
+inline static u_int32_t vlanTunnelEncodingLength(SFLExtended_vlan_tunnel *vlanTunnel) {
+    return labelStackEncodingLength(&vlanTunnel->stack);
+}
+
+
+inline static void putGenericCounters(SFLReceiver *receiver, SFLIf_counters *counters)
+{
+    putNet32(receiver, counters->ifIndex);
+    putNet32(receiver, counters->ifType);
+    putNet64(receiver, counters->ifSpeed);
+    putNet32(receiver, counters->ifDirection);
+    putNet32(receiver, counters->ifStatus);
+    putNet64(receiver, counters->ifInOctets);
+    putNet32(receiver, counters->ifInUcastPkts);
+    putNet32(receiver, counters->ifInMulticastPkts);
+    putNet32(receiver, counters->ifInBroadcastPkts);
+    putNet32(receiver, counters->ifInDiscards);
+    putNet32(receiver, counters->ifInErrors);
+    putNet32(receiver, counters->ifInUnknownProtos);
+    putNet64(receiver, counters->ifOutOctets);
+    putNet32(receiver, counters->ifOutUcastPkts);
+    putNet32(receiver, counters->ifOutMulticastPkts);
+    putNet32(receiver, counters->ifOutBroadcastPkts);
+    putNet32(receiver, counters->ifOutDiscards);
+    putNet32(receiver, counters->ifOutErrors);
+    putNet32(receiver, counters->ifPromiscuousMode);
+}
+
+
+/*_________________-----------------------------__________________
+  _________________      computeFlowSampleSize  __________________
+  -----------------_____________________________------------------
+*/
+
+static int computeFlowSampleSize(SFLReceiver *receiver, SFL_FLOW_SAMPLE_TYPE *fs)
+{
+    SFLFlow_sample_element *elem = fs->elements;
+#ifdef SFL_USE_32BIT_INDEX
+    u_int siz = 52; /* tag, length, sequence_number, ds_class, ds_index, sampling_rate,
+		       sample_pool, drops, inputFormat, input, outputFormat, output, number of elements */
+#else
+    u_int siz = 40; /* tag, length, sequence_number, source_id, sampling_rate,
+		       sample_pool, drops, input, output, number of elements */
+#endif
+
+    fs->num_elements = 0; /* we're going to count them again even if this was set by the client */
+    for(; elem != NULL; elem = elem->nxt) {
+	u_int elemSiz = 0;
+	fs->num_elements++;
+	siz += 8; /* tag, length */
+	switch(elem->tag) {
+	case SFLFLOW_HEADER:
+	    elemSiz = 16; /* header_protocol, frame_length, stripped, header_length */
+	    elemSiz += ((elem->flowType.header.header_length + 3) / 4) * 4; /* header, rounded up to nearest 4 bytes */
+	    break;
+	case SFLFLOW_ETHERNET: elemSiz = sizeof(SFLSampled_ethernet); break;
+	case SFLFLOW_IPV4: elemSiz = sizeof(SFLSampled_ipv4); break;
+	case SFLFLOW_IPV6: elemSiz = sizeof(SFLSampled_ipv6); break;
+	case SFLFLOW_EX_SWITCH: elemSiz = sizeof(SFLExtended_switch); break;
+	case SFLFLOW_EX_ROUTER: elemSiz = routerEncodingLength(&elem->flowType.router); break;
+	case SFLFLOW_EX_GATEWAY: elemSiz = gatewayEncodingLength(&elem->flowType.gateway); break;
+	case SFLFLOW_EX_USER: elemSiz = userEncodingLength(&elem->flowType.user); break;
+	case SFLFLOW_EX_URL: elemSiz = urlEncodingLength(&elem->flowType.url); break;
+	case SFLFLOW_EX_MPLS: elemSiz = mplsEncodingLength(&elem->flowType.mpls); break;
+	case SFLFLOW_EX_NAT: elemSiz = natEncodingLength(&elem->flowType.nat); break;
+	case SFLFLOW_EX_MPLS_TUNNEL: elemSiz = mplsTunnelEncodingLength(&elem->flowType.mpls_tunnel); break;
+	case SFLFLOW_EX_MPLS_VC: elemSiz = mplsVcEncodingLength(&elem->flowType.mpls_vc); break;
+	case SFLFLOW_EX_MPLS_FTN: elemSiz = mplsFtnEncodingLength(&elem->flowType.mpls_ftn); break;
+	case SFLFLOW_EX_MPLS_LDP_FEC: elemSiz = mplsLdpFecEncodingLength(&elem->flowType.mpls_ldp_fec); break;
+	case SFLFLOW_EX_VLAN_TUNNEL: elemSiz = vlanTunnelEncodingLength(&elem->flowType.vlan_tunnel); break;
+	default:
+	    sflError(receiver, "unexpected packet_data_tag");
+	    return -1;
+	    break;
+	}
+	// cache the element size, and accumulate it into the overall FlowSample size
+	elem->length = elemSiz;
+	siz += elemSiz;
+    }
+
+    return siz;
+}
+
+/*_________________-------------------------------__________________
+  _________________ sfl_receiver_writeFlowSample  __________________
+  -----------------_______________________________------------------
+*/
+
+int sfl_receiver_writeFlowSample(SFLReceiver *receiver, SFL_FLOW_SAMPLE_TYPE *fs)
+{
+    int packedSize;
+    if(fs == NULL) return -1;
+    if((packedSize = computeFlowSampleSize(receiver, fs)) == -1) return -1;
+
+    // check in case this one sample alone is too big for the datagram
+    // in fact - if it is even half as big then we should ditch it. Very
+    // important to avoid overruning the packet buffer.
+    if(packedSize > (int)(receiver->sFlowRcvrMaximumDatagramSize / 2)) {
+	sflError(receiver, "flow sample too big for datagram");
+	return -1;
+    }
+
+    // if the sample pkt is full enough so that this sample might put
+    // it over the limit, then we should send it now before going on.
+    if((receiver->sampleCollector.pktlen + packedSize) >= receiver->sFlowRcvrMaximumDatagramSize)
+	sendSample(receiver);
+    
+    receiver->sampleCollector.numSamples++;
+
+#ifdef SFL_USE_32BIT_INDEX
+    putNet32(receiver, SFLFLOW_SAMPLE_EXPANDED);
+#else
+    putNet32(receiver, SFLFLOW_SAMPLE);
+#endif
+
+    putNet32(receiver, packedSize - 8); // don't include tag and len
+    putNet32(receiver, fs->sequence_number);
+
+#ifdef SFL_USE_32BIT_INDEX
+    putNet32(receiver, fs->ds_class);
+    putNet32(receiver, fs->ds_index);
+#else
+    putNet32(receiver, fs->source_id);
+#endif
+
+    putNet32(receiver, fs->sampling_rate);
+    putNet32(receiver, fs->sample_pool);
+    putNet32(receiver, fs->drops);
+
+#ifdef SFL_USE_32BIT_INDEX
+    putNet32(receiver, fs->inputFormat);
+    putNet32(receiver, fs->input);
+    putNet32(receiver, fs->outputFormat);
+    putNet32(receiver, fs->output);
+#else
+    putNet32(receiver, fs->input);
+    putNet32(receiver, fs->output);
+#endif
+
+    putNet32(receiver, fs->num_elements);
+
+    {
+	SFLFlow_sample_element *elem = fs->elements;
+	for(; elem != NULL; elem = elem->nxt) {
+	    
+	    putNet32(receiver, elem->tag);
+	    putNet32(receiver, elem->length); // length cached in computeFlowSampleSize()
+	    
+	    switch(elem->tag) {
+	    case SFLFLOW_HEADER:
+		putNet32(receiver, elem->flowType.header.header_protocol);
+		putNet32(receiver, elem->flowType.header.frame_length);
+		putNet32(receiver, elem->flowType.header.stripped);
+		putNet32(receiver, elem->flowType.header.header_length);
+		/* the header */
+		memcpy(receiver->sampleCollector.datap, elem->flowType.header.header_bytes, elem->flowType.header.header_length);
+		/* round up to multiple of 4 to preserve alignment */
+		receiver->sampleCollector.datap += ((elem->flowType.header.header_length + 3) / 4);
+		break;
+	    case SFLFLOW_ETHERNET:
+		putNet32(receiver, elem->flowType.ethernet.eth_len);
+		putMACAddress(receiver, elem->flowType.ethernet.src_mac);
+		putMACAddress(receiver, elem->flowType.ethernet.dst_mac);
+		putNet32(receiver, elem->flowType.ethernet.eth_type);
+		break;
+	    case SFLFLOW_IPV4:
+		putNet32(receiver, elem->flowType.ipv4.length);
+		putNet32(receiver, elem->flowType.ipv4.protocol);
+		put32(receiver, elem->flowType.ipv4.src_ip.addr);
+		put32(receiver, elem->flowType.ipv4.dst_ip.addr);
+		putNet32(receiver, elem->flowType.ipv4.src_port);
+		putNet32(receiver, elem->flowType.ipv4.dst_port);
+		putNet32(receiver, elem->flowType.ipv4.tcp_flags);
+		putNet32(receiver, elem->flowType.ipv4.tos);
+		break;
+	    case SFLFLOW_IPV6:
+		putNet32(receiver, elem->flowType.ipv6.length);
+		putNet32(receiver, elem->flowType.ipv6.protocol);
+		put128(receiver, elem->flowType.ipv6.src_ip.addr);
+		put128(receiver, elem->flowType.ipv6.dst_ip.addr);
+		putNet32(receiver, elem->flowType.ipv6.src_port);
+		putNet32(receiver, elem->flowType.ipv6.dst_port);
+		putNet32(receiver, elem->flowType.ipv6.tcp_flags);
+		putNet32(receiver, elem->flowType.ipv6.priority);
+		break;
+	    case SFLFLOW_EX_SWITCH: putSwitch(receiver, &elem->flowType.sw); break;
+	    case SFLFLOW_EX_ROUTER: putRouter(receiver, &elem->flowType.router); break;
+	    case SFLFLOW_EX_GATEWAY: putGateway(receiver, &elem->flowType.gateway); break;
+	    case SFLFLOW_EX_USER: putUser(receiver, &elem->flowType.user); break;
+	    case SFLFLOW_EX_URL: putUrl(receiver, &elem->flowType.url); break;
+	    case SFLFLOW_EX_MPLS: putMpls(receiver, &elem->flowType.mpls); break;
+	    case SFLFLOW_EX_NAT: putNat(receiver, &elem->flowType.nat); break;
+	    case SFLFLOW_EX_MPLS_TUNNEL: putMplsTunnel(receiver, &elem->flowType.mpls_tunnel); break;
+	    case SFLFLOW_EX_MPLS_VC: putMplsVc(receiver, &elem->flowType.mpls_vc); break;
+	    case SFLFLOW_EX_MPLS_FTN: putMplsFtn(receiver, &elem->flowType.mpls_ftn); break;
+	    case SFLFLOW_EX_MPLS_LDP_FEC: putMplsLdpFec(receiver, &elem->flowType.mpls_ldp_fec); break;
+	    case SFLFLOW_EX_VLAN_TUNNEL: putVlanTunnel(receiver, &elem->flowType.vlan_tunnel); break;
+	    default:
+		sflError(receiver, "unexpected packet_data_tag");
+		return -1;
+		break;
+	    }
+	}
+    }
+
+    // sanity check
+    assert(((u_char *)receiver->sampleCollector.datap
+	    - (u_char *)receiver->sampleCollector.data
+	    - receiver->sampleCollector.pktlen)  == (u_int32_t)packedSize);
+
+    // update the pktlen
+    receiver->sampleCollector.pktlen = (u_char *)receiver->sampleCollector.datap - (u_char *)receiver->sampleCollector.data;
+    return packedSize;
+}
+
+/*_________________-----------------------------__________________
+  _________________ computeCountersSampleSize   __________________
+  -----------------_____________________________------------------
+*/
+
+static int computeCountersSampleSize(SFLReceiver *receiver, SFL_COUNTERS_SAMPLE_TYPE *cs)
+{
+    SFLCounters_sample_element *elem = cs->elements;
+#ifdef SFL_USE_32BIT_INDEX
+    u_int siz = 24; /* tag, length, sequence_number, ds_class, ds_index, number of elements */
+#else
+    u_int siz = 20; /* tag, length, sequence_number, source_id, number of elements */
+#endif
+
+    cs->num_elements = 0; /* we're going to count them again even if this was set by the client */
+    for(; elem != NULL; elem = elem->nxt) {
+	u_int elemSiz = 0;
+	cs->num_elements++;
+	siz += 8; /* tag, length */
+	switch(elem->tag) {
+	case SFLCOUNTERS_GENERIC:  elemSiz = sizeof(elem->counterBlock.generic); break;
+	case SFLCOUNTERS_ETHERNET: elemSiz = sizeof(elem->counterBlock.ethernet); break;
+	case SFLCOUNTERS_TOKENRING: elemSiz = sizeof(elem->counterBlock.tokenring); break;
+	case SFLCOUNTERS_VG: elemSiz = sizeof(elem->counterBlock.vg); break;
+	case SFLCOUNTERS_VLAN: elemSiz = sizeof(elem->counterBlock.vlan); break;
+	default:
+	    sflError(receiver, "unexpected counters_tag");
+	    return -1;
+	    break;
+	}
+	// cache the element size, and accumulate it into the overall FlowSample size
+	elem->length = elemSiz;
+	siz += elemSiz;
+    }
+    return siz;
+}
+
+/*_________________----------------------------------__________________
+  _________________ sfl_receiver_writeCountersSample __________________
+  -----------------__________________________________------------------
+*/
+
+int sfl_receiver_writeCountersSample(SFLReceiver *receiver, SFL_COUNTERS_SAMPLE_TYPE *cs)
+{
+    int packedSize;
+    if(cs == NULL) return -1;
+    // if the sample pkt is full enough so that this sample might put
+    // it over the limit, then we should send it now.
+    if((packedSize = computeCountersSampleSize(receiver, cs)) == -1) return -1;
+  
+    // check in case this one sample alone is too big for the datagram
+    // in fact - if it is even half as big then we should ditch it. Very
+    // important to avoid overruning the packet buffer.
+    if(packedSize > (int)(receiver->sFlowRcvrMaximumDatagramSize / 2)) {
+	sflError(receiver, "counters sample too big for datagram");
+	return -1;
+    }
+  
+    if((receiver->sampleCollector.pktlen + packedSize) >= receiver->sFlowRcvrMaximumDatagramSize)
+	sendSample(receiver);
+  
+    receiver->sampleCollector.numSamples++;
+  
+#ifdef SFL_USE_32BIT_INDEX
+    putNet32(receiver, SFLCOUNTERS_SAMPLE_EXPANDED);
+#else
+    putNet32(receiver, SFLCOUNTERS_SAMPLE);
+#endif
+
+    putNet32(receiver, packedSize - 8); // tag and length not included
+    putNet32(receiver, cs->sequence_number);
+
+#ifdef SFL_USE_32BIT_INDEX
+    putNet32(receiver, cs->ds_class);
+    putNet32(receiver, cs->ds_index);
+#else
+    putNet32(receiver, cs->source_id);
+#endif
+
+    putNet32(receiver, cs->num_elements);
+  
+    {
+	SFLCounters_sample_element *elem = cs->elements;
+	for(; elem != NULL; elem = elem->nxt) {
+	    
+	    putNet32(receiver, elem->tag);
+	    putNet32(receiver, elem->length); // length cached in computeCountersSampleSize()
+	    
+	    switch(elem->tag) {
+	    case SFLCOUNTERS_GENERIC:
+		putGenericCounters(receiver, &(elem->counterBlock.generic));
+		break;
+	    case SFLCOUNTERS_ETHERNET:
+		// all these counters are 32-bit
+		putNet32_run(receiver, &elem->counterBlock.ethernet, sizeof(elem->counterBlock.ethernet) / 4);
+		break;
+	    case SFLCOUNTERS_TOKENRING:
+		// all these counters are 32-bit
+		putNet32_run(receiver, &elem->counterBlock.tokenring, sizeof(elem->counterBlock.tokenring) / 4);
+		break;
+	    case SFLCOUNTERS_VG:
+		// mixed sizes
+		putNet32(receiver, elem->counterBlock.vg.dot12InHighPriorityFrames);
+		putNet64(receiver, elem->counterBlock.vg.dot12InHighPriorityOctets);
+		putNet32(receiver, elem->counterBlock.vg.dot12InNormPriorityFrames);
+		putNet64(receiver, elem->counterBlock.vg.dot12InNormPriorityOctets);
+		putNet32(receiver, elem->counterBlock.vg.dot12InIPMErrors);
+		putNet32(receiver, elem->counterBlock.vg.dot12InOversizeFrameErrors);
+		putNet32(receiver, elem->counterBlock.vg.dot12InDataErrors);
+		putNet32(receiver, elem->counterBlock.vg.dot12InNullAddressedFrames);
+		putNet32(receiver, elem->counterBlock.vg.dot12OutHighPriorityFrames);
+		putNet64(receiver, elem->counterBlock.vg.dot12OutHighPriorityOctets);
+		putNet32(receiver, elem->counterBlock.vg.dot12TransitionIntoTrainings);
+		putNet64(receiver, elem->counterBlock.vg.dot12HCInHighPriorityOctets);
+		putNet64(receiver, elem->counterBlock.vg.dot12HCInNormPriorityOctets);
+		putNet64(receiver, elem->counterBlock.vg.dot12HCOutHighPriorityOctets);
+		break;
+	    case SFLCOUNTERS_VLAN:
+		// mixed sizes
+		putNet32(receiver, elem->counterBlock.vlan.vlan_id);
+		putNet64(receiver, elem->counterBlock.vlan.octets);
+		putNet32(receiver, elem->counterBlock.vlan.ucastPkts);
+		putNet32(receiver, elem->counterBlock.vlan.multicastPkts);
+		putNet32(receiver, elem->counterBlock.vlan.broadcastPkts);
+		putNet32(receiver, elem->counterBlock.vlan.discards);
+		break;
+	    default:
+		sflError(receiver, "unexpected counters_tag");
+		return -1;
+		break;
+	    }
+	}
+    }
+    // sanity check
+    assert(((u_char *)receiver->sampleCollector.datap
+	    - (u_char *)receiver->sampleCollector.data
+	    - receiver->sampleCollector.pktlen)  == (u_int32_t)packedSize);
+
+    // update the pktlen
+    receiver->sampleCollector.pktlen = (u_char *)receiver->sampleCollector.datap - (u_char *)receiver->sampleCollector.data;
+    return packedSize;
+}
+
+/*_________________---------------------------------__________________
+  _________________ sfl_receiver_samplePacketsSent  __________________
+  -----------------_________________________________------------------
+*/
+
+u_int32_t sfl_receiver_samplePacketsSent(SFLReceiver *receiver)
+{
+    return receiver->sampleCollector.packetSeqNo;
+}
+
+/*_________________---------------------------__________________
+  _________________     sendSample            __________________
+  -----------------___________________________------------------
+*/
+
+static void sendSample(SFLReceiver *receiver)
+{  
+    /* construct and send out the sample, then reset for the next one... */
+    /* first fill in the header with the latest values */
+    /* version, agent_address and sub_agent_id were pre-set. */
+    u_int32_t hdrIdx = (receiver->agent->myIP.type == SFLADDRESSTYPE_IP_V6) ? 7 : 4;
+    receiver->sampleCollector.data[hdrIdx++] = htonl(++receiver->sampleCollector.packetSeqNo); /* seq no */
+    receiver->sampleCollector.data[hdrIdx++] = htonl((receiver->agent->now - receiver->agent->bootTime) * 1000); /* uptime */
+    receiver->sampleCollector.data[hdrIdx++] = htonl(receiver->sampleCollector.numSamples); /* num samples */
+    /* send */
+    if(receiver->agent->sendFn) (*receiver->agent->sendFn)(receiver->agent->magic,
+							   receiver->agent,
+							   receiver,
+							   (u_char *)receiver->sampleCollector.data, 
+							   receiver->sampleCollector.pktlen);
+    else {
+#ifdef SFLOW_DO_SOCKET
+	/* send it myself */
+	if (receiver->sFlowRcvrAddress.type == SFLADDRESSTYPE_IP_V6) {
+	    u_int32_t soclen = sizeof(struct sockaddr_in6);
+	    int result = sendto(receiver->agent->receiverSocket6,
+				receiver->sampleCollector.data,
+				receiver->sampleCollector.pktlen,
+				0,
+				(struct sockaddr *)&receiver->receiver6,
+				soclen);
+	    if(result == -1 && errno != EINTR) sfl_agent_sysError(receiver->agent, "receiver", "IPv6 socket sendto error");
+	    if(result == 0) sfl_agent_error(receiver->agent, "receiver", "IPv6 socket sendto returned 0");
+	}
+	else {
+	    u_int32_t soclen = sizeof(struct sockaddr_in);
+	    int result = sendto(receiver->agent->receiverSocket4,
+				receiver->sampleCollector.data,
+				receiver->sampleCollector.pktlen,
+				0,
+				(struct sockaddr *)&receiver->receiver4,
+				soclen);
+	    if(result == -1 && errno != EINTR) sfl_agent_sysError(receiver->agent, "receiver", "socket sendto error");
+	    if(result == 0) sfl_agent_error(receiver->agent, "receiver", "socket sendto returned 0");
+	}
+#endif
+    }
+
+    /* reset for the next time */
+    resetSampleCollector(receiver);
+}
+
+/*_________________---------------------------__________________
+  _________________   resetSampleCollector    __________________
+  -----------------___________________________------------------
+*/
+
+static void resetSampleCollector(SFLReceiver *receiver)
+{
+    receiver->sampleCollector.pktlen = 0;
+    receiver->sampleCollector.numSamples = 0;
+    /* point the datap to just after the header */
+    receiver->sampleCollector.datap = (receiver->agent->myIP.type == SFLADDRESSTYPE_IP_V6) ?
+	(receiver->sampleCollector.data + 10) :  (receiver->sampleCollector.data + 7);
+
+    receiver->sampleCollector.pktlen = (u_char *)receiver->sampleCollector.datap - (u_char *)receiver->sampleCollector.data;
+}
+
+/*_________________---------------------------__________________
+  _________________         sflError          __________________
+  -----------------___________________________------------------
+*/
+
+static void sflError(SFLReceiver *receiver, char *msg)
+{
+    sfl_agent_error(receiver->agent, "receiver", msg);
+    resetSampleCollector(receiver);
+}