FreeCalypso > hg > freecalypso-tools
view rvinterf/libg23/fmtdispatch.c @ 820:03457a66d860
buzplayer: add basic support for PWT
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Sun, 30 May 2021 03:39:58 +0000 |
parents | e7502631a0f9 |
children |
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/* * This libg23 module exports the format_g23_packet() function, which * validates the packet, then dispatches it to format_g23_trace(), * format_g23_sysprim() or format_g23_psprim() as appropriate, or * prints it in raw hex if malformed. */ #include <sys/types.h> #include <stdio.h> #include <string.h> #include <strings.h> static int basic_checks(rxpkt, rxpkt_len) u_char *rxpkt; { int i, c; if (rxpkt_len < 17) return(0); /* check version bits in the header byte */ if ((rxpkt[1] & 0xC0) != 0x80) return(0); /* check the length */ c = rxpkt[2] | rxpkt[3] << 8; if (c + 4 != rxpkt_len) return(0); /* ensure that the "from" and "to" are printable ASCII */ for (i = 8; i < 16; i++) { c = rxpkt[i]; if (c < ' ' || c > '~') return(0); } /* basic checks pass */ return(1); } static int psprim_extra_checks(rxpkt, rxpkt_len) u_char *rxpkt; { int i, c; if (rxpkt_len < 24) return(0); /* "original rcvr" field needs to be printable ASCII */ for (i = 16; i < 20; i++) { c = rxpkt[i]; if (c < ' ' || c > '~') return(0); } /* checks pass */ return(1); } static void print_unknown_bin(rxpkt, rxpkt_len, outbuf) u_char *rxpkt; char *outbuf; { int i; char *dp; dp = outbuf; strcpy(dp, "GPF UNK:"); dp += 8; for (i = 1; i < rxpkt_len; i++) { sprintf(dp, " %02X", rxpkt[i]); dp += 3; } *dp = '\0'; } static void print_old_ascii(rxpkt, rxpkt_len, outbuf) u_char *rxpkt; char *outbuf; { char *dp; int txtlen = rxpkt_len - 1; dp = outbuf; strcpy(dp, "GPF ASC: "); dp += 9; bcopy(rxpkt + 1, dp, txtlen); dp += txtlen; *dp = '\0'; } static int is_old_ascii(rxpkt, rxpkt_len) u_char *rxpkt; { int i, c; for (i = 1; i < rxpkt_len; i++) { c = rxpkt[i]; if (c < ' ' || c > '~') return(0); } return(1); } static void print_malformed(rxpkt, rxpkt_len, outbuf) u_char *rxpkt; char *outbuf; { if (is_old_ascii(rxpkt, rxpkt_len)) print_old_ascii(rxpkt, rxpkt_len, outbuf); else print_unknown_bin(rxpkt, rxpkt_len, outbuf); } void format_g23_packet(rxpkt, rxpkt_len, outbuf) u_char *rxpkt; char *outbuf; { if (!basic_checks(rxpkt, rxpkt_len)) { print_malformed(rxpkt, rxpkt_len, outbuf); return; } /* dispatch by type */ switch (rxpkt[1] & 0x30) { case 0x10: /* PS primitive */ if (psprim_extra_checks(rxpkt, rxpkt_len)) format_g23_psprim(rxpkt, rxpkt_len, outbuf); else print_malformed(rxpkt, rxpkt_len, outbuf); return; case 0x20: /* trace */ format_g23_trace(rxpkt, rxpkt_len, outbuf); return; case 0x30: /* system primitive */ format_g23_sysprim(rxpkt, rxpkt_len, outbuf); return; default: print_malformed(rxpkt, rxpkt_len, outbuf); } }