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author | rsc <devnull@localhost> | 2005-12-26 04:48:52 +0000 |
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committer | rsc <devnull@localhost> | 2005-12-26 04:48:52 +0000 |
commit | 87a52e0485d3281ebea6bf4b725aa8023690e96f (patch) | |
tree | 0abc2d2ddb875196177231639d3cb4519e814b9d /src/cmd/ip/snoopy/hdlc.c | |
parent | 35d26aa32167e84326cdb745c0e906393b8de71d (diff) | |
download | plan9port-87a52e0485d3281ebea6bf4b725aa8023690e96f.tar.gz plan9port-87a52e0485d3281ebea6bf4b725aa8023690e96f.tar.bz2 plan9port-87a52e0485d3281ebea6bf4b725aa8023690e96f.zip |
new goodies
Diffstat (limited to 'src/cmd/ip/snoopy/hdlc.c')
-rwxr-xr-x | src/cmd/ip/snoopy/hdlc.c | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/src/cmd/ip/snoopy/hdlc.c b/src/cmd/ip/snoopy/hdlc.c new file mode 100755 index 00000000..bed0c35a --- /dev/null +++ b/src/cmd/ip/snoopy/hdlc.c @@ -0,0 +1,174 @@ +#include <u.h> +#include <libc.h> +#include <ip.h> +#include "dat.h" +#include "protos.h" + +enum { + HDLC_frame= 0x7e, + HDLC_esc= 0x7d, + + /* PPP frame fields */ + PPP_addr= 0xff, + PPP_ctl= 0x3, + PPP_initfcs= 0xffff, + PPP_goodfcs= 0xf0b8, +}; + +/* + * Calculate FCS - rfc 1331 + */ +ushort fcstab[256] = +{ + 0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf, + 0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7, + 0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e, + 0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876, + 0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd, + 0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5, + 0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c, + 0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974, + 0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb, + 0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3, + 0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a, + 0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72, + 0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9, + 0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1, + 0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738, + 0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70, + 0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7, + 0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff, + 0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036, + 0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e, + 0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5, + 0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd, + 0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134, + 0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c, + 0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3, + 0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb, + 0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232, + 0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a, + 0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1, + 0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9, + 0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330, + 0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78 +}; + +static uchar inbuf[16*1024]; +static int inlen; + +static Mux p_mux[] = +{ + {"ppp", (PPP_addr<<8)|PPP_ctl, } , + {0} +}; + +enum +{ + Ot = 1 +}; + +static void +p_compile(Filter *f) +{ + Mux *m; + + for(m = p_mux; m->name != nil; m++) + if(strcmp(f->s, m->name) == 0){ + f->pr = m->pr; + f->ulv = m->val; + f->subop = Ot; + return; + } + sysfatal("unknown ethernet field or protocol: %s", f->s); +} + +static int +p_filter(Filter *f, Msg *m) +{ + ulong t; + + if(m->pe-m->ps < 2) + return 0; + + switch(f->subop){ + case Ot: + t = (m->ps[0]<<8)|m->ps[1]; + if(t != f->ulv) + return 0; + break; + } + return 1; +} + +static int +p_seprint(Msg *m) +{ + ulong t; + + if(m->pe-m->ps < 2) + return -1; + + t = (m->ps[0]<<8)|m->ps[1]; + m->ps += 2; + demux(p_mux, t, t, m, &dump); + + return 0; +} + +static int +p_framer(int fd, uchar *pkt, int pktlen) +{ + ushort fcs; + uchar *from, *efrom, *to, *eto; + int n; + ulong c; + + eto = pkt+pktlen; + for(;;){ + efrom = memchr(inbuf, HDLC_frame, inlen); + if(efrom == nil){ + if(inlen >= sizeof(inbuf)) + inlen = 0; + n = read(fd, inbuf+inlen, sizeof(inbuf)-inlen); + if(n <= 0) + break; + inlen += n; + continue; + } + + /* checksum and unescape the frame */ + fcs = PPP_initfcs; + to = pkt; + for(from = inbuf; from < efrom;){ + c = *from++; + if(c == HDLC_esc) + c = (*from++) ^ 0x20; + if(to < eto) + *to++ = c; + fcs = (fcs >> 8) ^ fcstab[(fcs ^ c) & 0xff]; + } + + /* move down anything that's left */ + inlen -= efrom+1-inbuf; + memmove(inbuf, efrom+1, inlen); + + /* accept if this is a good packet */ + if(fcs != PPP_goodfcs) + print("bad frame %ld %2.2ux %2.2ux!\n", to-pkt, pkt[0], pkt[1]); + else + return to-pkt; + } + return -1; +} + +Proto hdlc = +{ + "hdlc", + p_compile, + p_filter, + p_seprint, + p_mux, + nil, + p_framer, +}; |