From e0da9b0cfb5384982aef1e0c0d2c0cc46686fe0c Mon Sep 17 00:00:00 2001
From: XANTRONIX Development <dev@xantronix.com>
Date: Mon, 4 Feb 2019 22:15:33 -0600
Subject: [PATCH] Well, I suppose we all have mommies and daddies

---
 include/hexagram/can.h | 40 ++++++++++++++++++++
 src/Makefile           |  4 +-
 src/can.c              | 85 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 127 insertions(+), 2 deletions(-)
 create mode 100644 include/hexagram/can.h
 create mode 100644 src/can.c

diff --git a/include/hexagram/can.h b/include/hexagram/can.h
new file mode 100644
index 0000000..55fa34e
--- /dev/null
+++ b/include/hexagram/can.h
@@ -0,0 +1,40 @@
+#ifndef _HEXAGRAM_CAN_H
+#define _HEXAGRAM_CAN_H
+
+#include <stdint.h>
+#include <sys/types.h>
+#include <linux/can.h>
+
+#define HEXAGRAM_CAN_DUMP_MAGIC  "CAAN"
+#define HEXAGRAM_CAN_DUMP_ENDIAN 0x0a0b0c0d
+#define HEXAGRAM_CAN_DUMP_ENDIAN_SWAPPED 0x0d0c0b0a
+
+#define HEXAGRAM_CAN_DUMP_TYPE_UNKNOWN    0
+#define HEXAGRAM_CAN_DUMP_TYPE_SOCKETCAN 29
+
+typedef struct _hexagram_can_dump {
+    char magic[4];
+    uint32_t endian;
+    uint8_t type,
+            tsresol;
+    char iface[38];
+} hexagram_can_dump;
+
+typedef struct _hexagram_can_frame {
+    uint32_t timestamp_hi,
+             timestamp_lo;
+    struct can_frame frame;
+} hexagram_can_frame;
+
+typedef struct _hexagram_can_stream hexagram_can_stream;
+
+hexagram_can_stream *hexagram_can_stream_open_fd(int fd);
+
+void hexagram_can_stream_destroy(hexagram_can_stream *stream);
+
+int hexagram_can_stream_read(hexagram_can_stream *stream,
+                             uint32_t *timestamp_hi,
+                             uint32_t *timestamp_lo,
+                             struct can_frame *frame);
+
+#endif /* _HEXAGRAM_CAN_H */
diff --git a/src/Makefile b/src/Makefile
index 6c581bc..0cff3b6 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -7,10 +7,10 @@ CC		= $(CROSS)cc
 CFLAGS		+= -fPIC -I$(INCLUDE_PATH)
 LDFLAGS		=
 
-HEADERS		= pcapng.h
+HEADERS		= can.h pcapng.h
 HEADERS_LOCAL	= util.h
 
-OBJS		= pcapng.o
+OBJS		= can.o pcapng.o
 
 VERSION_MAJOR	= 0
 VERSION_MINOR	= 0.1
diff --git a/src/can.c b/src/can.c
new file mode 100644
index 0000000..41375ca
--- /dev/null
+++ b/src/can.c
@@ -0,0 +1,85 @@
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <hexagram/can.h>
+
+struct _hexagram_can_stream {
+    int fd;
+    uint32_t endian;
+    uint8_t tsresol;
+};
+
+hexagram_can_stream *hexagram_can_stream_open_fd(int fd) {
+    hexagram_can_stream *stream;
+    hexagram_can_dump dump;
+    ssize_t readlen;
+
+    if ((stream = malloc(sizeof(*stream))) == NULL) {
+        goto error_malloc;
+    }
+
+    if ((readlen = read(fd, &dump, sizeof(dump))) < 0) {
+        goto error_read;
+    }
+
+    if (memcmp(dump.magic, HEXAGRAM_CAN_DUMP_MAGIC, sizeof(dump.magic)) != 0) {
+        goto error_invalid_format;
+    }
+
+    switch (dump.endian) {
+        case HEXAGRAM_CAN_DUMP_ENDIAN:
+        case HEXAGRAM_CAN_DUMP_ENDIAN_SWAPPED:
+            break;
+
+        default:
+            goto error_invalid_format;
+    }
+
+    if (dump.type != HEXAGRAM_CAN_DUMP_TYPE_SOCKETCAN) {
+        goto error_invalid_format;
+    }
+
+    stream->fd      = fd;
+    stream->endian  = dump.endian;
+    stream->tsresol = dump.tsresol;
+
+    return stream;
+
+error_invalid_format:
+error_read:
+    free(stream);
+
+error_malloc:
+    return NULL;
+}
+
+void hexagram_can_stream_destroy(hexagram_can_stream *stream) {
+    memset(stream, '\0', sizeof(*stream));
+
+    free(stream);
+}
+
+int hexagram_can_stream_read(hexagram_can_stream *stream,
+                             uint32_t *timestamp_hi,
+                             uint32_t *timestamp_lo,
+                             struct can_frame *frame) {
+    ssize_t len;
+    hexagram_can_frame data;
+
+    if ((len = read(stream->fd, &data, sizeof(data))) < 0) {
+        goto error_io;
+    } else if (len < sizeof(data)) {
+        goto error_io;
+    }
+
+    *timestamp_hi = data.timestamp_hi;
+    *timestamp_lo = data.timestamp_lo;
+
+    memcpy(frame, &data.frame, sizeof(data.frame));
+
+    return 0;
+
+error_io:
+    return -1;
+}