[PATCH v5 2/3] graph: pcap capture for graph nodes

[Amit Prakash Shukla <amitprakashs@marvell.com>]

Implementation adds support to capture packets at each node with
packet metadata and node name.

Signed-off-by: Amit Prakash Shukla <amitprakashs@marvell.com>
---
v2:
 - Fixed code style issue
 - Fixed CI compilation issue on github-robot

v3:
 - Code review suggestion from Stephen
 - Fixed potential memory leak
 
v4:
 - Code review suggestion from Jerin

v5:
 - Code review suggestion from Jerin

 doc/guides/rel_notes/release_23_03.rst |   7 +
 lib/graph/graph.c                      |  17 +-
 lib/graph/graph_pcap.c                 | 216 +++++++++++++++++++++++++
 lib/graph/graph_pcap_private.h         | 116 +++++++++++++
 lib/graph/graph_populate.c             |  12 +-
 lib/graph/graph_private.h              |   5 +
 lib/graph/meson.build                  |   3 +-
 lib/graph/rte_graph.h                  |   5 +
 lib/graph/rte_graph_worker.h           |   9 ++
 9 files changed, 387 insertions(+), 3 deletions(-)
 create mode 100644 lib/graph/graph_pcap.c
 create mode 100644 lib/graph/graph_pcap_private.h

diff --git a/doc/guides/rel_notes/release_23_03.rst b/doc/guides/rel_notes/release_23_03.rst
index dab62508c4..e709df8b53 100644
--- a/doc/guides/rel_notes/release_23_03.rst
+++ b/doc/guides/rel_notes/release_23_03.rst
@@ -78,6 +78,10 @@ New Features
     ``rte_event_dev_config::nb_single_link_event_port_queues`` parameter
     required for eth_rx, eth_tx, crypto and timer eventdev adapters.
 
+* **Added pcap trace support in graph library.**
+
+  * Added support to capture packets at each graph node with packet metadata and
+    node name.
 
 Removed Items
 -------------
@@ -110,6 +114,9 @@ API Changes
 * Experimental function ``rte_pcapng_copy`` was updated to support comment
   section in enhanced packet block in pcapng library.
 
+* Experimental structures ``struct rte_graph_param``, ``struct rte_graph`` and
+  ``struct graph`` were updated to support pcap trace in graph library.
+
 ABI Changes
 -----------
 
diff --git a/lib/graph/graph.c b/lib/graph/graph.c
index 3a617cc369..a839a2803b 100644
--- a/lib/graph/graph.c
+++ b/lib/graph/graph.c
@@ -15,6 +15,7 @@
 #include <rte_string_fns.h>
 
 #include "graph_private.h"
+#include "graph_pcap_private.h"
 
 static struct graph_head graph_list = STAILQ_HEAD_INITIALIZER(graph_list);
 static rte_spinlock_t graph_lock = RTE_SPINLOCK_INITIALIZER;
@@ -228,7 +229,12 @@ graph_mem_fixup_node_ctx(struct rte_graph *graph)
 		node_db = node_from_name(name);
 		if (node_db == NULL)
 			SET_ERR_JMP(ENOLINK, fail, "Node %s not found", name);
-		node->process = node_db->process;
+
+		if (graph->pcap_enable) {
+			node->process = graph_pcap_dispatch;
+			node->original_process = node_db->process;
+		} else
+			node->process = node_db->process;
 	}
 
 	return graph;
@@ -242,6 +248,9 @@ graph_mem_fixup_secondary(struct rte_graph *graph)
 	if (graph == NULL || rte_eal_process_type() == RTE_PROC_PRIMARY)
 		return graph;
 
+	if (graph_pcap_file_open(graph->pcap_filename) || graph_pcap_mp_init())
+		graph_pcap_exit(graph);
+
 	return graph_mem_fixup_node_ctx(graph);
 }
 
@@ -323,11 +332,17 @@ rte_graph_create(const char *name, struct rte_graph_param *prm)
 	if (graph_has_isolated_node(graph))
 		goto graph_cleanup;
 
+	/* Initialize pcap config. */
+	graph_pcap_enable(prm->pcap_enable);
+
 	/* Initialize graph object */
 	graph->socket = prm->socket_id;
 	graph->src_node_count = src_node_count;
 	graph->node_count = graph_nodes_count(graph);
 	graph->id = graph_id;
+	graph->num_pkt_to_capture = prm->num_pkt_to_capture;
+	if (prm->pcap_filename)
+		rte_strscpy(graph->pcap_filename, prm->pcap_filename, RTE_GRAPH_PCAP_FILE_SZ);
 
 	/* Allocate the Graph fast path memory and populate the data */
 	if (graph_fp_mem_create(graph))
diff --git a/lib/graph/graph_pcap.c b/lib/graph/graph_pcap.c
new file mode 100644
index 0000000000..9cbd1b8fdb
--- /dev/null
+++ b/lib/graph/graph_pcap.c
@@ -0,0 +1,216 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(C) 2023 Marvell International Ltd.
+ */
+
+#include <errno.h>
+#include <pwd.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <rte_mbuf.h>
+#include <rte_pcapng.h>
+
+#include "rte_graph_worker.h"
+
+#include "graph_pcap_private.h"
+
+#define GRAPH_PCAP_BUF_SZ	128
+#define GRAPH_PCAP_NUM_PACKETS	1024
+#define GRAPH_PCAP_PKT_POOL	"graph_pcap_pkt_pool"
+#define GRAPH_PCAP_FILE_NAME	"dpdk_graph_pcap_capture_XXXXXX.pcapng"
+
+/* For multi-process, packets are captured in separate files. */
+static rte_pcapng_t *pcapng_fd;
+static bool pcap_enable;
+struct rte_mempool *pkt_mp;
+
+void
+graph_pcap_enable(bool val)
+{
+	pcap_enable = val;
+}
+
+int
+graph_pcap_is_enable(void)
+{
+	return pcap_enable;
+}
+
+void
+graph_pcap_exit(struct rte_graph *graph)
+{
+	if (rte_eal_process_type() == RTE_PROC_PRIMARY)
+		if (pkt_mp)
+			rte_mempool_free(pkt_mp);
+
+	if (pcapng_fd) {
+		rte_pcapng_close(pcapng_fd);
+		pcapng_fd = NULL;
+	}
+
+	/* Disable pcap. */
+	graph->pcap_enable = 0;
+	graph_pcap_enable(0);
+}
+
+static int
+graph_pcap_default_path_get(char **dir_path)
+{
+	struct passwd *pwd;
+	char *home_dir;
+
+	/* First check for shell environment variable */
+	home_dir = getenv("HOME");
+	if (home_dir == NULL) {
+		graph_warn("Home env not preset.");
+		/* Fallback to password file entry */
+		pwd = getpwuid(getuid());
+		if (pwd == NULL)
+			return -EINVAL;
+
+		home_dir = pwd->pw_dir;
+	}
+
+	/* Append default pcap file to directory */
+	if (asprintf(dir_path, "%s/%s", home_dir, GRAPH_PCAP_FILE_NAME) == -1)
+		return -ENOMEM;
+
+	return 0;
+}
+
+int
+graph_pcap_file_open(const char *filename)
+{
+	int fd;
+	char file_name[RTE_GRAPH_PCAP_FILE_SZ];
+	char *pcap_dir;
+
+	if (pcapng_fd)
+		goto done;
+
+	if (!filename || filename[0] == '\0') {
+		if (graph_pcap_default_path_get(&pcap_dir) < 0)
+			return -1;
+		snprintf(file_name, RTE_GRAPH_PCAP_FILE_SZ, "%s", pcap_dir);
+		free(pcap_dir);
+	} else {
+		snprintf(file_name, RTE_GRAPH_PCAP_FILE_SZ, "%s_XXXXXX.pcapng",
+			 filename);
+	}
+
+	fd = mkstemps(file_name, strlen(".pcapng"));
+	if (fd < 0) {
+		graph_err("mkstemps() failure");
+		return -1;
+	}
+
+	graph_info("pcap filename: %s", file_name);
+
+	/* Open a capture file */
+	pcapng_fd = rte_pcapng_fdopen(fd, NULL, NULL, "Graph pcap tracer",
+				      NULL);
+	if (pcapng_fd == NULL) {
+		graph_err("Graph rte_pcapng_fdopen failed.");
+		close(fd);
+		return -1;
+	}
+
+done:
+	return 0;
+}
+
+int
+graph_pcap_mp_init(void)
+{
+	pkt_mp = rte_mempool_lookup(GRAPH_PCAP_PKT_POOL);
+	if (pkt_mp)
+		goto done;
+
+	/* Make a pool for cloned packets */
+	pkt_mp = rte_pktmbuf_pool_create_by_ops(GRAPH_PCAP_PKT_POOL,
+			IOV_MAX + RTE_GRAPH_BURST_SIZE,	0, 0,
+			rte_pcapng_mbuf_size(RTE_MBUF_DEFAULT_BUF_SIZE),
+			SOCKET_ID_ANY, "ring_mp_mc");
+	if (pkt_mp == NULL) {
+		graph_err("Cannot create mempool for graph pcap capture.");
+		return -1;
+	}
+
+done:
+	return 0;
+}
+
+int
+graph_pcap_init(struct graph *graph)
+{
+	struct rte_graph *graph_data = graph->graph;
+
+	if (graph_pcap_file_open(graph->pcap_filename) < 0)
+		goto error;
+
+	if (graph_pcap_mp_init() < 0)
+		goto error;
+
+	/* User configured number of packets to capture. */
+	if (graph->num_pkt_to_capture)
+		graph_data->nb_pkt_to_capture = graph->num_pkt_to_capture;
+	else
+		graph_data->nb_pkt_to_capture = GRAPH_PCAP_NUM_PACKETS;
+
+	/* All good. Now populate data for secondary process. */
+	rte_strscpy(graph_data->pcap_filename, graph->pcap_filename, RTE_GRAPH_PCAP_FILE_SZ);
+	graph_data->pcap_enable = 1;
+
+	return 0;
+
+error:
+	graph_pcap_exit(graph_data);
+	graph_pcap_enable(0);
+	graph_err("Graph pcap initialization failed. Disabling pcap trace.");
+	return -1;
+}
+
+uint16_t
+graph_pcap_dispatch(struct rte_graph *graph,
+			      struct rte_node *node, void **objs,
+			      uint16_t nb_objs)
+{
+	struct rte_mbuf *mbuf_clones[RTE_GRAPH_BURST_SIZE];
+	char buffer[GRAPH_PCAP_BUF_SZ];
+	uint64_t i, num_packets;
+	struct rte_mbuf *mbuf;
+	ssize_t len;
+
+	if (!nb_objs || (graph->nb_pkt_captured >= graph->nb_pkt_to_capture))
+		goto done;
+
+	num_packets = graph->nb_pkt_to_capture - graph->nb_pkt_captured;
+	/* nb_objs will never be greater than RTE_GRAPH_BURST_SIZE */
+	if (num_packets > nb_objs)
+		num_packets = nb_objs;
+
+	snprintf(buffer, GRAPH_PCAP_BUF_SZ, "%s: %s", graph->name, node->name);
+
+	for (i = 0; i < num_packets; i++) {
+		struct rte_mbuf *mc;
+		mbuf = (struct rte_mbuf *)objs[i];
+
+		mc = rte_pcapng_copy(mbuf->port, 0, mbuf, pkt_mp, mbuf->pkt_len,
+				     rte_get_tsc_cycles(), 0, buffer);
+		if (mc == NULL)
+			break;
+
+		mbuf_clones[i] = mc;
+	}
+
+	/* write it to capture file */
+	len = rte_pcapng_write_packets(pcapng_fd, mbuf_clones, i);
+	rte_pktmbuf_free_bulk(mbuf_clones, i);
+	if (len <= 0)
+		goto done;
+
+	graph->nb_pkt_captured += i;
+
+done:
+	return node->original_process(graph, node, objs, nb_objs);
+}
diff --git a/lib/graph/graph_pcap_private.h b/lib/graph/graph_pcap_private.h
new file mode 100644
index 0000000000..2ec772072c
--- /dev/null
+++ b/lib/graph/graph_pcap_private.h
@@ -0,0 +1,116 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(C) 2023 Marvell International Ltd.
+ */
+
+#ifndef _RTE_GRAPH_PCAP_PRIVATE_H_
+#define _RTE_GRAPH_PCAP_PRIVATE_H_
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include "graph_private.h"
+
+/**
+ * @internal
+ *
+ * Pcap trace enable/disable function.
+ *
+ * The function is called to enable/disable graph pcap trace functionality.
+ *
+ * @param val
+ *   Value to be set to enable/disable graph pcap trace.
+ */
+void graph_pcap_enable(bool val);
+
+/**
+ * @internal
+ *
+ * Check graph pcap trace is enable/disable.
+ *
+ * The function is called to check if the graph pcap trace is enabled/disabled.
+ *
+ * @return
+ *   - 1: Enable
+ *   - 0: Disable
+ */
+int graph_pcap_is_enable(void);
+
+/**
+ * @internal
+ *
+ * Initialise graph pcap trace functionality.
+ *
+ * The function invoked to allocate mempool.
+ *
+ * @return
+ *   0 on success and -1 on failure.
+ */
+int graph_pcap_mp_init(void);
+
+/**
+ * @internal
+ *
+ * Initialise graph pcap trace functionality.
+ *
+ * The function invoked to open pcap file.
+ *
+ * @param filename
+ *   Pcap filename.
+ *
+ * @return
+ *   0 on success and -1 on failure.
+ */
+int graph_pcap_file_open(const char *filename);
+
+/**
+ * @internal
+ *
+ * Initialise graph pcap trace functionality.
+ *
+ * The function invoked when the graph pcap trace is enabled. This function
+ * open's pcap file and allocates mempool. Information needed for secondary
+ * process is populated.
+ *
+ * @param graph
+ *   Pointer to graph structure.
+ *
+ * @return
+ *   0 on success and -1 on failure.
+ */
+int graph_pcap_init(struct graph *graph);
+
+/**
+ * @internal
+ *
+ * Exit graph pcap trace functionality.
+ *
+ * The function is called to exit graph pcap trace and close open fd's and
+ * free up memory. Pcap trace is also disabled.
+ *
+ * @param graph
+ *   Pointer to graph structure.
+ */
+void graph_pcap_exit(struct rte_graph *graph);
+
+/**
+ * @internal
+ *
+ * Capture mbuf metadata and node metadata to a pcap file.
+ *
+ * When graph pcap trace enabled, this function is invoked prior to each node
+ * and mbuf, node metadata is parsed and captured in a pcap file.
+ *
+ * @param graph
+ *   Pointer to the graph object.
+ * @param node
+ *   Pointer to the node object.
+ * @param objs
+ *   Pointer to an array of objects to be processed.
+ * @param nb_objs
+ *   Number of objects in the array.
+ */
+uint16_t graph_pcap_dispatch(struct rte_graph *graph,
+				   struct rte_node *node, void **objs,
+				   uint16_t nb_objs);
+
+#endif /* _RTE_GRAPH_PCAP_PRIVATE_H_ */
diff --git a/lib/graph/graph_populate.c b/lib/graph/graph_populate.c
index 102fd6c29b..2c0844ce92 100644
--- a/lib/graph/graph_populate.c
+++ b/lib/graph/graph_populate.c
@@ -9,6 +9,7 @@
 #include <rte_memzone.h>
 
 #include "graph_private.h"
+#include "graph_pcap_private.h"
 
 static size_t
 graph_fp_mem_calc_size(struct graph *graph)
@@ -75,7 +76,11 @@ graph_nodes_populate(struct graph *_graph)
 		memset(node, 0, sizeof(*node));
 		node->fence = RTE_GRAPH_FENCE;
 		node->off = off;
-		node->process = graph_node->node->process;
+		if (graph_pcap_is_enable()) {
+			node->process = graph_pcap_dispatch;
+			node->original_process = graph_node->node->process;
+		} else
+			node->process = graph_node->node->process;
 		memcpy(node->name, graph_node->node->name, RTE_GRAPH_NAMESIZE);
 		pid = graph_node->node->parent_id;
 		if (pid != RTE_NODE_ID_INVALID) { /* Cloned node */
@@ -183,6 +188,8 @@ graph_fp_mem_populate(struct graph *graph)
 	int rc;
 
 	graph_header_popluate(graph);
+	if (graph_pcap_is_enable())
+		graph_pcap_init(graph);
 	graph_nodes_populate(graph);
 	rc = graph_node_nexts_populate(graph);
 	rc |= graph_src_nodes_populate(graph);
@@ -227,6 +234,9 @@ graph_nodes_mem_destroy(struct rte_graph *graph)
 int
 graph_fp_mem_destroy(struct graph *graph)
 {
+	if (graph_pcap_is_enable())
+		graph_pcap_exit(graph->graph);
+
 	graph_nodes_mem_destroy(graph->graph);
 	return rte_memzone_free(graph->mz);
 }
diff --git a/lib/graph/graph_private.h b/lib/graph/graph_private.h
index f9a85c8926..7d1b30b8ac 100644
--- a/lib/graph/graph_private.h
+++ b/lib/graph/graph_private.h
@@ -22,6 +22,7 @@ extern int rte_graph_logtype;
 			__func__, __LINE__, RTE_FMT_TAIL(__VA_ARGS__, )))
 
 #define graph_err(...) GRAPH_LOG(ERR, __VA_ARGS__)
+#define graph_warn(...) GRAPH_LOG(WARNING, __VA_ARGS__)
 #define graph_info(...) GRAPH_LOG(INFO, __VA_ARGS__)
 #define graph_dbg(...) GRAPH_LOG(DEBUG, __VA_ARGS__)
 
@@ -100,6 +101,10 @@ struct graph {
 	/**< Memory size of the graph. */
 	int socket;
 	/**< Socket identifier where memory is allocated. */
+	uint64_t num_pkt_to_capture;
+	/**< Number of packets to be captured per core. */
+	char pcap_filename[RTE_GRAPH_PCAP_FILE_SZ];
+	/**< pcap file name/path. */
 	STAILQ_HEAD(gnode_list, graph_node) node_list;
 	/**< Nodes in a graph. */
 };
diff --git a/lib/graph/meson.build b/lib/graph/meson.build
index c7327549e8..3526d1b5d4 100644
--- a/lib/graph/meson.build
+++ b/lib/graph/meson.build
@@ -14,7 +14,8 @@ sources = files(
         'graph_debug.c',
         'graph_stats.c',
         'graph_populate.c',
+        'graph_pcap.c',
 )
 headers = files('rte_graph.h', 'rte_graph_worker.h')
 
-deps += ['eal']
+deps += ['eal', 'pcapng']
diff --git a/lib/graph/rte_graph.h b/lib/graph/rte_graph.h
index b32c4bc217..c9a77297fc 100644
--- a/lib/graph/rte_graph.h
+++ b/lib/graph/rte_graph.h
@@ -35,6 +35,7 @@ extern "C" {
 
 #define RTE_GRAPH_NAMESIZE 64 /**< Max length of graph name. */
 #define RTE_NODE_NAMESIZE 64  /**< Max length of node name. */
+#define RTE_GRAPH_PCAP_FILE_SZ 64 /**< Max length of pcap file name. */
 #define RTE_GRAPH_OFF_INVALID UINT32_MAX /**< Invalid graph offset. */
 #define RTE_NODE_ID_INVALID UINT32_MAX   /**< Invalid node id. */
 #define RTE_EDGE_ID_INVALID UINT16_MAX   /**< Invalid edge id. */
@@ -164,6 +165,10 @@ struct rte_graph_param {
 	uint16_t nb_node_patterns;  /**< Number of node patterns. */
 	const char **node_patterns;
 	/**< Array of node patterns based on shell pattern. */
+
+	bool pcap_enable; /**< Pcap enable. */
+	uint64_t num_pkt_to_capture; /**< Number of packets to capture. */
+	char *pcap_filename; /**< Filename in which packets to be captured.*/
 };
 
 /**
diff --git a/lib/graph/rte_graph_worker.h b/lib/graph/rte_graph_worker.h
index fc6fee48c8..438595b15c 100644
--- a/lib/graph/rte_graph_worker.h
+++ b/lib/graph/rte_graph_worker.h
@@ -44,6 +44,12 @@ struct rte_graph {
 	rte_graph_t id;	/**< Graph identifier. */
 	int socket;	/**< Socket ID where memory is allocated. */
 	char name[RTE_GRAPH_NAMESIZE];	/**< Name of the graph. */
+	bool pcap_enable;	        /**< Pcap trace enabled. */
+	/** Number of packets captured per core. */
+	uint64_t nb_pkt_captured;
+	/** Number of packets to capture per core. */
+	uint64_t nb_pkt_to_capture;
+	char pcap_filename[RTE_GRAPH_PCAP_FILE_SZ];  /**< Pcap filename. */
 	uint64_t fence;			/**< Fence. */
 } __rte_cache_aligned;
 
@@ -64,6 +70,9 @@ struct rte_node {
 	char parent[RTE_NODE_NAMESIZE];	/**< Parent node name. */
 	char name[RTE_NODE_NAMESIZE];	/**< Name of the node. */
 
+	/** Original process function when pcap is enabled. */
+	rte_node_process_t original_process;
+
 	/* Fast path area  */
 #define RTE_NODE_CTX_SZ 16
 	uint8_t ctx[RTE_NODE_CTX_SZ] __rte_cache_aligned; /**< Node Context. */
-- 
2.25.1