diff options
Diffstat (limited to 'xdlc.c')
| -rw-r--r-- | xdlc.c | 59 |
1 files changed, 44 insertions, 15 deletions
@@ -2,7 +2,7 @@ * Routines for use by various SDLC-derived protocols, such as HDLC * and its derivatives LAPB, IEEE 802.2 LLC, etc.. * - * $Id: xdlc.c,v 1.4 1999/08/23 22:47:13 guy Exp $ + * $Id: xdlc.c,v 1.5 1999/08/23 23:24:36 guy Exp $ * * Ethereal - Network traffic analyzer * By Gerald Combs <gerald@unicom.net> @@ -66,6 +66,31 @@ #define XDLC_REJ 0x08 /* Reject */ #define XDLC_SREJ 0x0C /* Selective reject */ +/* + * U-format modifiers. + */ +#define XDLC_U_MODIFIER_MASK 0xEC +#define XDLC_UI 0x00 /* Unnumbered Information */ +#define XDLC_UP 0x20 /* Unnumbered Poll */ +#define XDLC_DISC 0x40 /* Disconnect (command) */ +#define XDLC_RD 0x40 /* Request Disconnect (response) */ +#define XDLC_UA 0x60 /* Unnumbered Acknowledge */ +#define XDLC_SNRM 0x80 /* Set Normal Response Mode */ +#define XDLC_TEST 0xC0 /* Test */ +#define XDLC_SIM 0x04 /* Set Initialization Mode (command) */ +#define XDLC_RIM 0x04 /* Request Initialization Mode (response) */ +#define XDLC_FRMR 0x84 /* Frame reject */ +#define XDLC_CFGR 0xC4 /* Configure */ +#define XDLC_SARM 0x0C /* Set Asynchronous Response Mode (command) */ +#define XDLC_DM 0x0C /* Disconnected mode (response) */ +#define XDLC_SABM 0x2C /* Set Asynchronous Balanced Mode */ +#define XDLC_SARME 0x4C /* Set Asynchronous Response Mode Extended */ +#define XDLC_SABME 0x6C /* Set Asynchronous Balanced Mode Extended */ +#define XDLC_RESET 0x8C /* Reset */ +#define XDLC_XID 0xAC /* Exchange identification */ +#define XDLC_SNRME 0xCC /* Set Normal Response Mode Extended */ +#define XDLC_BCN 0xEC /* Beacon */ + static const value_string stype_vals[] = { { XDLC_RR, "Receiver ready" }, { XDLC_RNR, "Receiver not ready" }, @@ -167,9 +192,9 @@ get_xdlc_control(const u_char *pd, int offset, int is_response, int is_extended) case XDLC_S: /* - * Supervisory frame. + * Supervisory frame - no higher-layer payload. */ - return XDLC_S; + return FALSE; case XDLC_U: /* @@ -185,17 +210,15 @@ get_xdlc_control(const u_char *pd, int offset, int is_response, int is_extended) control = pd[offset]; /* - * Return the modifier as well as the XDLC_U bits, so that - * our caller knows whether the packet is UI or something - * else. + * This frame has payload only if it's a UI frame. */ - return control & (XDLC_U_MODIFIER_MASK|0x03); + return (control & XDLC_U_MODIFIER_MASK) == XDLC_UI; default: /* - * Information frame. + * Information frame - has higher-layer payload. */ - return XDLC_I; + return TRUE; } } @@ -297,7 +320,11 @@ dissect_xdlc_control(const u_char *pd, int offset, frame_data *fd, "Supervisory frame", NULL)); } } - return XDLC_S; + + /* + * Supervisory frames have no higher-layer payload to be analyzed. + */ + return FALSE; case XDLC_U: /* @@ -349,11 +376,9 @@ dissect_xdlc_control(const u_char *pd, int offset, frame_data *fd, } /* - * Return the modifier as well as the XDLC_U bits, so that - * our caller knows whether the packet is UI or something - * else. + * This frame has payload only if it's a UI frame. */ - return control & (XDLC_U_MODIFIER_MASK|0x03); + return (control & XDLC_U_MODIFIER_MASK) == XDLC_UI; default: /* @@ -415,6 +440,10 @@ dissect_xdlc_control(const u_char *pd, int offset, frame_data *fd, NULL, "Information frame")); } } - return XDLC_I; + + /* + * Information frames have higher-layer payload to be analyzed. + */ + return TRUE; } } |