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>

5 files changed, 182 insertions, 1 deletions

diff --git a/net/Makefile b/net/Makefile
index 826544f05f..2a700c8401 100644
--- a/net/Makefile
+++ b/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
diff --git a/net/eth-uclass.c b/net/eth-uclass.c
index 1d5d2f03b7..3bd98b01ad 100644
--- a/net/eth-uclass.c
+++ b/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;
 }
 
diff --git a/net/eth_legacy.c b/net/eth_legacy.c
index 850f362d87..41f5263526 100644
--- a/net/eth_legacy.c
+++ b/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)
diff --git a/net/net.c b/net/net.c
index 40511db645..74a8a36b5a 100644
--- a/net/net.c
+++ b/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;
diff --git a/net/pcap.c b/net/pcap.c
new file mode 100644
index 0000000000..4036d8a3fa
--- /dev/null
+++ b/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;
+}