[U-Boot] [PATCH v3 1/2] net: introduce packet capture support

* [U-Boot] [PATCH v3 1/2] net: introduce packet capture support
@ 2019-06-22 18:49 Ramon Fried
  2019-06-22 18:49 ` [U-Boot] [PATCH 2/2] doc: pcap: add pcap cmd documentation Ramon Fried
                   ` (2 more replies)
  0 siblings, 3 replies; 8+ messages in thread
From: Ramon Fried @ 2019-06-22 18:49 UTC (permalink / raw)
  To: u-boot

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>
---
v2: Fix type assignmnet to header.ts_sec
v3: Several suggestion changes by Bin and Alex:
   * Change to implementation to command based.
   * Added counters for incoming/outgoing packets.
   * Support clearing the capture for multiple captures.
   * Added documentation (separate patch).

 cmd/Kconfig   |   7 +++
 cmd/net.c     |  63 +++++++++++++++++++++
 include/net.h |  56 +++++++++++++++++++
 net/Makefile  |   1 +
 net/net.c     |   8 +++
 net/pcap.c    | 152 ++++++++++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 287 insertions(+)
 create mode 100644 net/pcap.c

diff --git a/cmd/Kconfig b/cmd/Kconfig
index 0badcb3fe0..638f979f28 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -1239,6 +1239,13 @@ 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
diff --git a/cmd/net.c b/cmd/net.c
index 89721b8f8b..5022f1dbcc 100644
--- a/cmd/net.c
+++ b/cmd/net.c
@@ -457,3 +457,66 @@ U_BOOT_CMD(
 );
 
 #endif  /* CONFIG_CMD_LINK_LOCAL */
+
+#if defined(CONFIG_CMD_PCAP)
+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),
+);
+#endif /* CONFIG_CMD_PCAP */
diff --git a/include/net.h b/include/net.h
index 44b32385c4..f0289c3cde 100644
--- a/include/net.h
+++ b/include/net.h
@@ -630,6 +630,58 @@ bool arp_is_waiting(void);		/* Waiting for ARP reply? */
 void net_set_icmp_handler(rxhand_icmp_f *f); /* Set ICMP RX handler */
 void net_set_timeout_handler(ulong, thand_f *);/* Set timeout handler */
 
+/* PCAP extension */
+
+/**
+ * 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);
+
 /* Network loop state */
 enum net_loop_state {
 	NETLOOP_CONTINUE,
@@ -658,6 +710,10 @@ static inline void net_send_packet(uchar *pkt, int len)
 {
 	/* Currently no way to return errors from eth_send() */
 	(void) eth_send(pkt, len);
+
+#if defined(CONFIG_CMD_PCAP)
+	pcap_post(pkt, len, true);
+#endif
 }
 
 /*
diff --git a/net/Makefile b/net/Makefile
index ce36362168..d70a7c6834 100644
--- a/net/Makefile
+++ b/net/Makefile
@@ -20,6 +20,7 @@ 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
diff --git a/net/net.c b/net/net.c
index 58b0417cbe..b6b5a49153 100644
--- a/net/net.c
+++ b/net/net.c
@@ -671,6 +671,11 @@ 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;
 }
 
@@ -1083,6 +1088,9 @@ 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;
diff --git a/net/pcap.c b/net/pcap.c
new file mode 100644
index 0000000000..071bfeb510
--- /dev/null
+++ b/net/pcap.c
@@ -0,0 +1,152 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 Ramon Fried <rfried.dev@gmail.com>
+ */
+
+#include <common.h>
+#include <net.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 ((pos + len + sizeof(header)) >= max_size) {
+		buffer_full = true;
+		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++;
+
+	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);
+
+	if (buffer_full)
+		printf("\t!!! Buffer is full, consider increasing buffer size !!!\n");
+
+	return 0;
+}
+
+bool pcap_active(void)
+{
+	return running;
+}
-- 
2.22.0

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