diff options
Diffstat (limited to 'wiretap/pcap-common.c')
| -rw-r--r-- | wiretap/pcap-common.c | 126 |
1 files changed, 80 insertions, 46 deletions
diff --git a/wiretap/pcap-common.c b/wiretap/pcap-common.c index 3a60794..a4b02cb 100644 --- a/wiretap/pcap-common.c +++ b/wiretap/pcap-common.c @@ -1931,13 +1931,26 @@ struct usb_device_setup_hdr { PBSWAP64((guint8 *)fieldp); \ } -struct can_socketcan_hdr { - guint32 can_id; /* CAN ID and flags */ - guint8 payload_length; /* Frame payload length */ - guint8 padding; - guint8 reserved1; - guint8 reserved2; -}; +/* + * Offset and length of the CAN ID field in the CAN classic/CAN FD + * SocketCAN header. + */ +#define CAN_CANFD_CAN_ID_OFFSET 0 +#define CAN_CANFD_CAN_ID_LEN 4 + +/* + * Offsets and lengths of fields in the CAN XL SocketCAN header. + */ +#define CANXL_PRIORITY_VCID_OFFSET 0 +#define CANXL_PRIORITY_VCID_LEN 4 +#define CANXL_FLAGS_OFFSET (CANXL_PRIORITY_VCID_OFFSET + CANXL_PRIORITY_VCID_LEN) +#define CANXL_FLAGS_LEN 1 +#define CANXL_SDU_TYPE_OFFSET (CANXL_FLAGS_OFFSET + CANXL_FLAGS_LEN) +#define CANXL_SDU_TYPE_LEN 1 +#define CANXL_PAYLOAD_LENGTH_OFFSET (CANXL_SDU_TYPE_OFFSET + CANXL_SDU_TYPE_LEN) +#define CANXL_PAYLOAD_LENGTH_LEN 2 +#define CANXL_ACCEPTANCE_FIELD_OFFSET (CANXL_PAYLOAD_LENGTH_OFFSET + CANXL_PAYLOAD_LENGTH_LEN) +#define CANXL_ACCEPTANCE_FIELD_LEN 4 /* * CAN fake link-layer headers in Linux cooked packets. @@ -1951,15 +1964,65 @@ struct can_socketcan_hdr { /* * The protocols we have to check for. */ -#define LINUX_SLL_P_CAN 0x000C /* Controller Area Network */ +#define LINUX_SLL_P_CAN 0x000C /* Controller Area Network classic */ #define LINUX_SLL_P_CANFD 0x000D /* Controller Area Network flexible data rate */ +#define LINUX_SLL_P_CANXL 0x000E /* Controller Area Network extended length */ + +static void +pcap_byteswap_can_socketcan_pseudoheader(guint packet_size, guint16 protocol, + guint8 *pd) +{ + switch (protocol) { + + case LINUX_SLL_P_CAN: + case LINUX_SLL_P_CANFD: + /* + * CAN classic or CAN FD; byte-swap the ID/flags field + * into our host byte order. + * + * Make sure we have the entire field. + */ + if (packet_size < (CAN_CANFD_CAN_ID_OFFSET + CAN_CANFD_CAN_ID_LEN)) { + /* Not enough data to have the full CAN ID */ + return; + } + PBSWAP32(&pd[CAN_CANFD_CAN_ID_OFFSET]); + break; + + case LINUX_SLL_P_CANXL: + /* + * CAN classic or CAN FD; byte-swap the priority-and-VCID + * field, the payload length, ad the acceptance field + * into our host byte order. + */ + if (packet_size < (CANXL_PRIORITY_VCID_OFFSET + CANXL_PRIORITY_VCID_LEN)) { + /* Not enough data to have the full priority/VCID field */ + return; + } + PBSWAP32(&pd[CANXL_PRIORITY_VCID_OFFSET]); + if (packet_size < (CANXL_PAYLOAD_LENGTH_OFFSET + CANXL_PAYLOAD_LENGTH_LEN)) { + /* Not enough data to have the full payload length field */ + return; + } + PBSWAP16(&pd[CANXL_PAYLOAD_LENGTH_OFFSET]); + if (packet_size < (CANXL_ACCEPTANCE_FIELD_OFFSET + CANXL_ACCEPTANCE_FIELD_LEN)) { + /* Not enough data to have the full payload length field */ + return; + } + PBSWAP32(&pd[CANXL_ACCEPTANCE_FIELD_OFFSET]); + break; + + default: + /* Not a CAN packet; nothing to fix */ + return; + } +} static void pcap_byteswap_linux_sll_pseudoheader(wtap_rec *rec, guint8 *pd) { guint packet_size; guint16 protocol; - struct can_socketcan_hdr *can_socketcan_phdr; /* * Minimum of captured and actual length (just in case the @@ -1975,26 +2038,12 @@ pcap_byteswap_linux_sll_pseudoheader(wtap_rec *rec, guint8 *pd) return; } - protocol = pntoh16(&pd[LINUX_SLL_PROTOCOL_OFFSET]); - if (protocol != LINUX_SLL_P_CAN && protocol != LINUX_SLL_P_CANFD) { - /* Not a CAN packet; nothing to fix */ - return; - } - /* - * Greasy hack, but we never directly dereference any of - * the fields in *can_socketcan_phdr, we just get offsets - * of and addresses of its members and byte-swap it with a - * byte-at-a-time macro, so it's alignment-safe. + * Byte-swap the SocketCAN pseudoheader, if we have one. */ - can_socketcan_phdr = (struct can_socketcan_hdr *)(void *)(pd + LINUX_SLL_LEN); - - if (packet_size < LINUX_SLL_LEN + sizeof(can_socketcan_phdr->can_id)) { - /* Not enough data to have the full CAN ID */ - return; - } - - PBSWAP32((guint8 *)&can_socketcan_phdr->can_id); + protocol = pntoh16(&pd[LINUX_SLL_PROTOCOL_OFFSET]); + pcap_byteswap_can_socketcan_pseudoheader(packet_size - LINUX_SLL_LEN, + protocol, pd + LINUX_SLL_LEN); } static void @@ -2002,7 +2051,6 @@ pcap_byteswap_linux_sll2_pseudoheader(wtap_rec *rec, guint8 *pd) { guint packet_size; guint16 protocol; - struct can_socketcan_hdr *can_socketcan_phdr; /* * Minimum of captured and actual length (just in case the @@ -2018,26 +2066,12 @@ pcap_byteswap_linux_sll2_pseudoheader(wtap_rec *rec, guint8 *pd) return; } - protocol = pntoh16(&pd[LINUX_SLL2_PROTOCOL_OFFSET]); - if (protocol != LINUX_SLL_P_CAN && protocol != LINUX_SLL_P_CANFD) { - /* Not a CAN packet; nothing to fix */ - return; - } - /* - * Greasy hack, but we never directly dereference any of - * the fields in *can_socketcan_phdr, we just get offsets - * of and addresses of its members and byte-swap it with a - * byte-at-a-time macro, so it's alignment-safe. + * Byte-swap the SocketCAN pseudoheader, if we have one. */ - can_socketcan_phdr = (struct can_socketcan_hdr *)(void *)(pd + LINUX_SLL2_LEN); - - if (packet_size < LINUX_SLL2_LEN + sizeof(can_socketcan_phdr->can_id)) { - /* Not enough data to have the full CAN ID */ - return; - } - - PBSWAP32((guint8 *)&can_socketcan_phdr->can_id); + protocol = pntoh16(&pd[LINUX_SLL2_PROTOCOL_OFFSET]); + pcap_byteswap_can_socketcan_pseudoheader(packet_size - LINUX_SLL2_LEN, + protocol, pd + LINUX_SLL2_LEN); } static void |