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Diffstat (limited to 'src/vnet/ipfix-export/ipfix_doc.rst')
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diff --git a/src/vnet/ipfix-export/ipfix_doc.rst b/src/vnet/ipfix-export/ipfix_doc.rst new file mode 100644 index 00000000000..ac660b4bc93 --- /dev/null +++ b/src/vnet/ipfix-export/ipfix_doc.rst @@ -0,0 +1,360 @@ +.. _ipfix_doc: + +IPFIX support +============= + +VPP includes a high-performance IPFIX record exporter. This note +explains how to use the internal APIs to export IPFIX data, and how to +configure and send the required IPFIX templates. + +As you’ll see, a bit of typing is required. + +First: create an ipfix “report” +------------------------------- + +Include the flow report header file, fill out a @ref +vnet_flow_report_add_del_args_t structure, and call +vnet_flow_report_add_del. + +.. code:: c + + #include <vnet/ipfix-export/flow_report.h> + /* Defined in flow_report.h, of interest when constructing reports */ + + /* ipfix field definitions for a particular report */ + typedef struct + { + u32 info_element; + u32 size; + } ipfix_report_element_t; + + /* Report add/del argument structure */ + typedef struct + { + /* Callback to flush current ipfix packet / frame */ + vnet_flow_data_callback_t *flow_data_callback; + + /* Callback to build the template packet rewrite string */ + vnet_flow_rewrite_callback_t *rewrite_callback; + + /* List of ipfix elements in the report */ + ipfix_report_element_t *report_elements; + u32 n_report_elements; + /* Kept in flow report, used e.g. by flow classifier */ + opaque_t opaque; + /* Add / delete a report */ + int is_add; + /* Ipfix "domain-ID", see RFC, set as desired */ + u32 domain_id; + /* ipfix packet source port, often set to UDP_DST_PORT_ipfix */ + u16 src_port; + /* Set by ipfix infra, needed to send data packets */ + u32 *stream_indexp; + } vnet_flow_report_add_del_args_t; + + /* Private header file contents */ + + /* Report ipfix element definition */ + #define foreach_simple_report_ipfix_element \ + _(sourceIPv4Address, 4) \ + _(destinationIPv4Address, 4) \ + _(sourceTransportPort, 2) \ + _(destinationTransportPort, 2) \ + _(protocolIdentifier, 1) \ + _(flowStartMicroseconds, 8) \ + _(flowEndMicroseconds, 8) + + static ipfix_report_element_t simple_report_elements[] = { + #define _(a,b) {a,b}, + foreach_simple_report_ipfix_element + #undef _ + }; + + typedef struct + { + /** Buffers and frames, per thread */ + vlib_buffer_t **buffers_by_thread; + vlib_frame_t **frames_by_thread; + u32 *next_record_offset_by_thread; + + /** Template ID's */ + u16 *template_ids; + + /** Time reference pair */ + u64 usec_time_0; + f64 vlib_time_0; + + /** Stream index */ + u32 stream_index; + + /* Convenience */ + flow_report_main_t *flow_report_main; + vlib_main_t *vlib_main; + vnet_main_t *vnet_main; + } my_logging_main_t; + + extern my_logging_main_t my_logging_main; + + ... + + /* Recitations */ + flow_report_main_t *frm = &flow_report_main; + my_logging_main_t *mlm = &my_logging_main; + vnet_flow_report_add_del_args_t a; + int rv; + u16 template_id; + + ... + + /* Init function: set up time reference pair */ + mlm->vlib_time_0 = vlib_time_now (vm); + mlm->milisecond_time_0 = unix_time_now_nsec () * 1e-6; + + ... + + /* Create a report */ + memset (&a, 0, sizeof (a)); + a.is_add = 1 /* to enable the report */; + a.domain_id = 1 /* pick a domain ID */; + a.src_port = UDP_DST_PORT_ipfix /* src port for reports */; + + /* Use the generic template packet rewrite string generator */ + a.rewrite_callback = vnet_flow_rewrite_generic_callback; + + /* Supply a list of ipfix report elements */ + a.report_elements = simple_report_elements; + a.n_report_elements = ARRAY_LEN (simple_report_elements); + + /* Pointer to the ipfix stream index, set by the report infra */ + a.stream_indexp = &mlm->stream_index; + a.flow_data_callback = my_flow_data_callback; + + /* Create the report */ + rv = vnet_flow_report_add_del (frm, &a, &template_id); + if (rv) + oops... + + /* Save the template-ID for later use */ + mlm->template_id = template_id; + +Several things are worth describing in more detail. + +vnet_flow_rewrite_generic_callback programming +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +This generic callback helps build ipfix template packets. When +registering an ipfix report, pass an (array, count) of ipfix elements as +shown above. + +my_flow_data_callback +~~~~~~~~~~~~~~~~~~~~~ + +The ipfix flow export infrastructure calls this callback to flush the +current ipfix packet; to make sure that ipfix data is not retained for +an unreasonably long period of time. + +We typically code it as shown below, to call an application-specific +function with (uninteresting arguments), and “do_flush = 1”: + +.. code:: c + + + vlib_frame_t *my_flow_data_callback + (flow_report_main_t * frm, + flow_report_t * fr, + vlib_frame_t * f, + u32 * to_next, u32 node_index) + { + + my_buffer_flow_record (0, ... , 0, 1 /* do_flush */); + return f; + } + +my_flow_data_header +~~~~~~~~~~~~~~~~~~~ + +This function creates the packet header for an ipfix data packet + +.. code:: c + + + static inline void + my_flow_report_header (flow_report_main_t * frm, + vlib_buffer_t * b0, u32 * offset) + { + my_logging_main_t *mlm = &my_logging_main; + flow_report_stream_t *stream; + ip4_ipfix_template_packet_t *tp; + ipfix_message_header_t *h = 0; + + + ipfix_set_header_t *s = 0; + ip4_header_t *ip; + udp_header_t *udp; + + stream = &frm->streams[mlm->stream_index]; + + b0->current_data = 0; + b0->current_length = sizeof (*ip) + sizeof (*udp) + sizeof (*h) + + sizeof (*s); + b0->flags |= (VLIB_BUFFER_TOTAL_LENGTH_VALID | VNET_BUFFER_F_FLOW_REPORT); + vnet_buffer (b0)->sw_if_index[VLIB_RX] = 0; + vnet_buffer (b0)->sw_if_index[VLIB_TX] = frm->fib_index; + tp = vlib_buffer_get_current (b0); + ip = (ip4_header_t *) & tp->ip4; + udp = (udp_header_t *) (ip + 1); + h = (ipfix_message_header_t *) (udp + 1); + s = (ipfix_set_header_t *) (h + 1); + + ip->ip_version_and_header_length = 0x45; + ip->ttl = 254; + ip->protocol = IP_PROTOCOL_UDP; + ip->flags_and_fragment_offset = 0; + ip->src_address.as_u32 = frm->src_address.as_u32; + ip->dst_address.as_u32 = frm->ipfix_collector.as_u32; + udp->src_port = clib_host_to_net_u16 (stream->src_port); + udp->dst_port = clib_host_to_net_u16 (frm->collector_port); + udp->checksum = 0; + + h->export_time = clib_host_to_net_u32 ((u32) + (((f64) frm->unix_time_0) + + (vlib_time_now (frm->vlib_main) - + frm->vlib_time_0))); + h->sequence_number = clib_host_to_net_u32 (stream->sequence_number++); + h->domain_id = clib_host_to_net_u32 (stream->domain_id); + + *offset = (u32) (((u8 *) (s + 1)) - (u8 *) tp); + } + +### fixup and transmit a flow record + +.. code:: c + + + static inline void + my_send_ipfix_pkt (flow_report_main_t * frm, + vlib_frame_t * f, vlib_buffer_t * b0, u16 template_id) + { + ip4_ipfix_template_packet_t *tp; + ipfix_message_header_t *h = 0; + ipfix_set_header_t *s = 0; + ip4_header_t *ip; + udp_header_t *udp; + vlib_main_t *vm = frm->vlib_main; + + tp = vlib_buffer_get_current (b0); + ip = (ip4_header_t *) & tp->ip4; + udp = (udp_header_t *) (ip + 1); + h = (ipfix_message_header_t *) (udp + 1); + s = (ipfix_set_header_t *) (h + 1); + + s->set_id_length = ipfix_set_id_length (template_id, + b0->current_length - + (sizeof (*ip) + sizeof (*udp) + + sizeof (*h))); + h->version_length = version_length (b0->current_length - + (sizeof (*ip) + sizeof (*udp))); + + ip->length = clib_host_to_net_u16 (b0->current_length); + ip->checksum = ip4_header_checksum (ip); + udp->length = clib_host_to_net_u16 (b0->current_length - sizeof (*ip)); + + if (frm->udp_checksum) + { + udp->checksum = ip4_tcp_udp_compute_checksum (vm, b0, ip); + if (udp->checksum == 0) + udp->checksum = 0xffff; + } + + ASSERT (ip4_header_checksum_is_valid (ip)); + + vlib_put_frame_to_node (vm, ip4_lookup_node.index, f); + } + +### my_buffer_flow_record + +This is the key routine which paints individual flow records into an +ipfix packet under construction. It’s pretty straightforward (albeit +stateful) vpp data-plane code. The code shown below is thread-safe by +construction. + +.. code:: c + + static inline void + my_buffer_flow_record_internal (my_flow_record_t * rp, int do_flush, + u32 thread_index) + { + vlib_main_t *vm = vlib_mains[thread_index]; + my_logging_main_t *mlm = &jvp_ipfix_main; + flow_report_main_t *frm = &flow_report_main; + vlib_frame_t *f; + vlib_buffer_t *b0 = 0; + u32 bi0 = ~0; + u32 offset; + + b0 = mlm->buffers_by_thread[thread_index]; + + if (PREDICT_FALSE (b0 == 0)) + { + if (do_flush) + return; + + if (vlib_buffer_alloc (vm, &bi0, 1) != 1) + { + clib_warning ("can't allocate ipfix data buffer"); + return; + } + + b0 = vlib_get_buffer (vm, bi0); + offset = 0; + mlm->buffers_by_thread[thread_index] = b0; + } + else + { + bi0 = vlib_get_buffer_index (vm, b0); + offset = mlm->next_record_offset_by_thread[thread_index]; + } + + f = mlm->frames_by_thread[thread_index]; + if (PREDICT_FALSE (f == 0)) + { + u32 *to_next; + f = vlib_get_frame_to_node (vm, ip4_lookup_node.index); + mlm->frames_by_thread[thread_index] = f; + to_next = vlib_frame_vector_args (f); + to_next[0] = bi0; + f->n_vectors = 1; + mlm->frames_by_thread[thread_index] = f; + } + + if (PREDICT_FALSE (offset == 0)) + my_flow_report_header (frm, b0, &offset); + + if (PREDICT_TRUE (do_flush == 0)) + { + /* Paint the new ipfix data record into the buffer */ + clib_memcpy (b0->data + offset, rp, sizeof (*rp)); + offset += sizeof (*rp); + b0->current_length += sizeof (*rp); + } + + if (PREDICT_FALSE (do_flush || (offset + sizeof (*rp)) > frm->path_mtu)) + { + /* Nothing to send? */ + if (offset == 0) + return; + + send_ipfix_pkt (frm, f, b0, mlm->template_ids[0]); + mlm->buffers_by_thread[thread_index] = 0; + mlm->frames_by_thread[thread_index] = 0; + offset = 0; + } + mlm->next_record_offset_by_thread[thread_index] = offset; + } + + static void + my_buffer_flow_record (my_flow_record_t * rp, int do_flush) + { + u32 thread_index = vlib_get_thread_index(); + my_buffer_flow_record_internal (rp, do_flush, thread_index); + } |