net: introduce packet capture support

Add support for capturing ethernet packets and storing
them in memory in PCAP(2.4) format, later to be analyzed by
any PCAP viewer software (IE. Wireshark)

This feature greatly assist debugging network issues such
as detecting dropped packets, packet corruption etc.

Signed-off-by: Ramon Fried <rfried.dev@gmail.com>
Reviewed-by: Alex Marginean <alexm.osslist@gmail.com>
Tested-by: Alex Marginean <alexm.osslist@gmail.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>

cmd/Kconfig

@@ -1339,6 +1339,13 @@ config BOOTP_NTPSERVER
 	bool "Request & store 'ntpserverip' from BOOTP/DHCP server"
 	depends on CMD_BOOTP
 
+config CMD_PCAP
+	bool "pcap capture"
+	help
+	  Selecting this will allow capturing all Ethernet packets and store
+	  them in physical memory in a PCAP formated file,
+	  later to be analyzed by PCAP reader application (IE. WireShark).
+
 config BOOTP_PXE
 	bool "Send PXE client arch to BOOTP/DHCP server"
 	default y

cmd/Makefile

@@ -103,6 +103,7 @@ obj-$(CONFIG_CMD_NVEDIT_EFI) += nvedit_efi.o
 obj-$(CONFIG_CMD_ONENAND) += onenand.o
 obj-$(CONFIG_CMD_OSD) += osd.o
 obj-$(CONFIG_CMD_PART) += part.o
+obj-$(CONFIG_CMD_PCAP) += pcap.o
 ifdef CONFIG_PCI
 obj-$(CONFIG_CMD_PCI) += pci.o
 endif

cmd/pcap.c

@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2019
+ * Ramon Fried <rfried.dev@gmail.com>
+ */
+
+#include <common.h>
+#include <command.h>
+#include <net.h>
+#include <net/pcap.h>
+
+static int do_pcap_init(cmd_tbl_t *cmdtp, int flag, int argc,
+			char * const argv[])
+{
+	phys_addr_t addr;
+	unsigned int size;
+
+	if (argc != 3)
+		return CMD_RET_USAGE;
+
+	addr = simple_strtoul(argv[1], NULL, 16);
+	size = simple_strtoul(argv[2], NULL, 10);
+
+	return pcap_init(addr, size) ? CMD_RET_FAILURE : CMD_RET_SUCCESS;
+}
+
+static int do_pcap_start(cmd_tbl_t *cmdtp, int flag, int argc,
+			 char * const argv[])
+{
+	return pcap_start_stop(true) ? CMD_RET_FAILURE : CMD_RET_SUCCESS;
+}
+
+static int do_pcap_stop(cmd_tbl_t *cmdtp, int flag, int argc,
+			char * const argv[])
+{
+	return pcap_start_stop(false) ? CMD_RET_FAILURE : CMD_RET_SUCCESS;
+}
+
+static int do_pcap_status(cmd_tbl_t *cmdtp, int flag, int argc,
+			  char * const argv[])
+{
+	return pcap_print_status() ? CMD_RET_FAILURE : CMD_RET_SUCCESS;
+}
+
+static int do_pcap_clear(cmd_tbl_t *cmdtp, int flag, int argc,
+			 char * const argv[])
+{
+	return pcap_clear() ? CMD_RET_FAILURE : CMD_RET_SUCCESS;
+}
+
+static char pcap_help_text[] =
+	"- network packet capture\n\n"
+	"pcap\n"
+	"pcap init\t\t\t<addr> <max_size>\n"
+	"pcap start\t\t\tstart capture\n"
+	"pcap stop\t\t\tstop capture\n"
+	"pcap status\t\t\tprint status\n"
+	"pcap clear\t\t\tclear capture buffer\n"
+	"\n"
+	"With:\n"
+	"\t<addr>: user address to which pcap will be stored (hexedcimal)\n"
+	"\t<max_size>: Maximum size of pcap file (decimal)\n"
+	"\n";
+
+U_BOOT_CMD_WITH_SUBCMDS(pcap, "pcap", pcap_help_text,
+			U_BOOT_SUBCMD_MKENT(init, 3, 0, do_pcap_init),
+			U_BOOT_SUBCMD_MKENT(start, 1, 0, do_pcap_start),
+			U_BOOT_SUBCMD_MKENT(stop, 1, 0, do_pcap_stop),
+			U_BOOT_SUBCMD_MKENT(status, 1, 0, do_pcap_status),
+			U_BOOT_SUBCMD_MKENT(clear, 1, 0, do_pcap_clear),
+);

include/net/pcap.h

@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright 2019
+ * Ramon Fried <rfried.dev@gmail.com>
+ */
+
+/**
+ * pcap_init() - Initialize PCAP memory buffer
+ *
+ * @paddr	physicaly memory address to store buffer
+ * @size	maximum size of capture file in memory
+ *
+ * @return	0 on success, -ERROR on error
+ */
+int pcap_init(phys_addr_t paddr, unsigned long size);
+
+/**
+ * pcap_start_stop() - start / stop pcap capture
+ *
+ * @start	if true, start capture if false stop capture
+ *
+ * @return	0 on success, -ERROR on error
+ */
+int pcap_start_stop(bool start);
+
+/**
+ * pcap_clear() - clear pcap capture buffer and statistics
+ *
+ * @return	0 on success, -ERROR on error
+ */
+int pcap_clear(void);
+
+/**
+ * pcap_print_status() - print status of pcap capture
+ *
+ * @return	0 on success, -ERROR on error
+ */
+int pcap_print_status(void);
+
+/**
+ * pcap_active() - check if pcap is enabled
+ *
+ * @return	TRUE if active, FALSE if not.
+ */
+bool pcap_active(void);
+
+/**
+ * pcap_post() - Post a packet to PCAP file
+ *
+ * @packet:	packet to post
+ * @len:	packet length in bytes
+ * @outgoing	packet direction (outgoing/incoming)
+ * @return	0 on success, -ERROR on error
+ */
+int pcap_post(const void *packet, size_t len, bool outgoing);

net/Makefile

@@ -22,6 +22,7 @@ obj-$(CONFIG_CMD_LINK_LOCAL) += link_local.o
 obj-$(CONFIG_NET)      += net.o
 obj-$(CONFIG_CMD_NFS)  += nfs.o
 obj-$(CONFIG_CMD_PING) += ping.o
+obj-$(CONFIG_CMD_PCAP) += pcap.o
 obj-$(CONFIG_CMD_RARP) += rarp.o
 obj-$(CONFIG_CMD_SNTP) += sntp.o
 obj-$(CONFIG_CMD_TFTPBOOT) += tftp.o

net/eth-uclass.c

@@ -11,6 +11,7 @@
 #include <net.h>
 #include <dm/device-internal.h>
 #include <dm/uclass-internal.h>
+#include <net/pcap.h>
 #include "eth_internal.h"
 
 DECLARE_GLOBAL_DATA_PTR;
@@ -344,6 +345,10 @@ int eth_send(void *packet, int length)
 		/* We cannot completely return the error at present */
 		debug("%s: send() returned error %d\n", __func__, ret);
 	}
+#if defined(CONFIG_CMD_PCAP)
+	if (ret >= 0)
+		pcap_post(packet, length, true);
+#endif
 	return ret;
 }
 

net/eth_legacy.c

@@ -11,6 +11,7 @@
 #include <net.h>
 #include <phy.h>
 #include <linux/errno.h>
+#include <net/pcap.h>
 #include "eth_internal.h"
 
 DECLARE_GLOBAL_DATA_PTR;
@@ -352,10 +353,17 @@ int eth_is_active(struct eth_device *dev)
 
 int eth_send(void *packet, int length)
 {
+	int ret;
+
 	if (!eth_current)
 		return -ENODEV;
 
-	return eth_current->send(eth_current, packet, length);
+	ret = eth_current->send(eth_current, packet, length);
+#if defined(CONFIG_CMD_PCAP)
+	if (ret >= 0)
+		pcap_post(packet, lengeth, true);
+#endif
+	return ret;
 }
 
 int eth_rx(void)

net/net.c

@@ -96,6 +96,9 @@
 #include <net.h>
 #include <net/fastboot.h>
 #include <net/tftp.h>
+#if defined(CONFIG_CMD_PCAP)
+#include <net/pcap.h>
+#endif
 #if defined(CONFIG_LED_STATUS)
 #include <miiphy.h>
 #include <status_led.h>
@@ -672,6 +675,11 @@ done:
 	net_set_icmp_handler(NULL);
 #endif
 	net_set_state(prev_net_state);
+
+#if defined(CONFIG_CMD_PCAP)
+	if (pcap_active())
+		pcap_print_status();
+#endif
 	return ret;
 }
 
@@ -1084,6 +1092,9 @@ void net_process_received_packet(uchar *in_packet, int len)
 
 	debug_cond(DEBUG_NET_PKT, "packet received\n");
 
+#if defined(CONFIG_CMD_PCAP)
+	pcap_post(in_packet, len, false);
+#endif
 	net_rx_packet = in_packet;
 	net_rx_packet_len = len;
 	et = (struct ethernet_hdr *)in_packet;

net/pcap.c

@@ -0,0 +1,156 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 Ramon Fried <rfried.dev@gmail.com>
+ */
+
+#include <common.h>
+#include <net.h>
+#include <net/pcap.h>
+#include <time.h>
+#include <asm/io.h>
+
+#define LINKTYPE_ETHERNET	1
+
+static bool initialized;
+static bool running;
+static bool buffer_full;
+static void *buf;
+static unsigned int max_size;
+static unsigned int pos;
+
+static unsigned long incoming_count;
+static unsigned long outgoing_count;
+
+struct pcap_header {
+	u32 magic;
+	u16 version_major;
+	u16 version_minor;
+	s32 thiszone;
+	u32 sigfigs;
+	u32 snaplen;
+	u32 network;
+};
+
+struct pcap_packet_header {
+	u32 ts_sec;
+	u32 ts_usec;
+	u32 incl_len;
+	u32 orig_len;
+};
+
+static struct pcap_header file_header = {
+	.magic = 0xa1b2c3d4,
+	.version_major = 2,
+	.version_minor = 4,
+	.snaplen = 65535,
+	.network = LINKTYPE_ETHERNET,
+};
+
+int pcap_init(phys_addr_t paddr, unsigned long size)
+{
+	buf = map_physmem(paddr, size, 0);
+	if (!buf) {
+		printf("Failed mapping PCAP memory\n");
+		return -ENOMEM;
+	}
+
+	printf("PCAP capture initialized: addr: 0x%lx max length: %lu\n",
+	       (unsigned long)buf, size);
+
+	memcpy(buf, &file_header, sizeof(file_header));
+	pos = sizeof(file_header);
+	max_size = size;
+	initialized = true;
+	running = false;
+	buffer_full = false;
+	incoming_count = 0;
+	outgoing_count = 0;
+	return 0;
+}
+
+int pcap_start_stop(bool start)
+{
+	if (!initialized) {
+		printf("error: pcap was not initialized\n");
+		return -ENODEV;
+	}
+
+	running = start;
+
+	return 0;
+}
+
+int pcap_clear(void)
+{
+	if (!initialized) {
+		printf("error: pcap was not initialized\n");
+		return -ENODEV;
+	}
+
+	pos = sizeof(file_header);
+	incoming_count = 0;
+	outgoing_count = 0;
+	buffer_full = false;
+
+	printf("pcap capture cleared\n");
+	return 0;
+}
+
+int pcap_post(const void *packet, size_t len, bool outgoing)
+{
+	struct pcap_packet_header header;
+	u64 cur_time = timer_get_us();
+
+	if (!initialized || !running || !buf)
+		return -ENODEV;
+
+	if (buffer_full)
+		return -ENOMEM;
+
+	if ((pos + len + sizeof(header)) >= max_size) {
+		buffer_full = true;
+		printf("\n!!! Buffer is full, consider increasing buffer size !!!\n");
+		return -ENOMEM;
+	}
+
+	header.ts_sec = cur_time / 1000000;
+	header.ts_usec = cur_time % 1000000;
+	header.incl_len = len;
+	header.orig_len = len;
+
+	memcpy(buf + pos, &header, sizeof(header));
+	pos += sizeof(header);
+	memcpy(buf + pos, packet, len);
+	pos += len;
+
+	if (outgoing)
+		outgoing_count++;
+	else
+		incoming_count++;
+
+	env_set_hex("pcapsize", pos);
+
+	return 0;
+}
+
+int pcap_print_status(void)
+{
+	if (!initialized) {
+		printf("pcap was not initialized\n");
+		return -ENODEV;
+	}
+	printf("PCAP status:\n");
+	printf("\tInitialized addr: 0x%lx\tmax length: %u\n",
+	       (unsigned long)buf, max_size);
+	printf("\tStatus: %s.\t file size: %u\n", running ? "Active" : "Idle",
+	       pos);
+	printf("\tIncoming packets: %lu Outgoing packets: %lu\n",
+	       incoming_count, outgoing_count);
+
+	return 0;
+}
+
+bool pcap_active(void)
+{
+	return running;
+}