diff options
Diffstat (limited to 'os/ip/gre.c')
| -rw-r--r-- | os/ip/gre.c | 282 |
1 files changed, 282 insertions, 0 deletions
diff --git a/os/ip/gre.c b/os/ip/gre.c new file mode 100644 index 00000000..96106331 --- /dev/null +++ b/os/ip/gre.c @@ -0,0 +1,282 @@ +#include "u.h" +#include "../port/lib.h" +#include "mem.h" +#include "dat.h" +#include "fns.h" +#include "../port/error.h" + +#include "ip.h" + +#define DPRINT if(0)print + +enum +{ + GRE_IPONLY = 12, /* size of ip header */ + GRE_IPPLUSGRE = 12, /* minimum size of GRE header */ + IP_GREPROTO = 47, + + GRErxms = 200, + GREtickms = 100, + GREmaxxmit = 10, +}; + +typedef struct GREhdr +{ + /* ip header */ + uchar vihl; /* Version and header length */ + uchar tos; /* Type of service */ + uchar len[2]; /* packet length (including headers) */ + uchar id[2]; /* Identification */ + uchar frag[2]; /* Fragment information */ + uchar Unused; + uchar proto; /* Protocol */ + uchar cksum[2]; /* checksum */ + uchar src[4]; /* Ip source */ + uchar dst[4]; /* Ip destination */ + + /* gre header */ + uchar flags[2]; + uchar eproto[2]; /* encapsulation protocol */ +} GREhdr; + +typedef struct GREpriv GREpriv; +struct GREpriv +{ + int raw; /* Raw GRE mode */ + + /* non-MIB stats */ + ulong csumerr; /* checksum errors */ + ulong lenerr; /* short packet */ +}; + +static void grekick(void *x, Block *bp); + +static char* +greconnect(Conv *c, char **argv, int argc) +{ + Proto *p; + char *err; + Conv *tc, **cp, **ecp; + + err = Fsstdconnect(c, argv, argc); + if(err != nil) + return err; + + /* make sure noone's already connected to this other sys */ + p = c->p; + qlock(p); + ecp = &p->conv[p->nc]; + for(cp = p->conv; cp < ecp; cp++){ + tc = *cp; + if(tc == nil) + break; + if(tc == c) + continue; + if(tc->rport == c->rport && ipcmp(tc->raddr, c->raddr) == 0){ + err = "already connected to that addr/proto"; + ipmove(c->laddr, IPnoaddr); + ipmove(c->raddr, IPnoaddr); + break; + } + } + qunlock(p); + + if(err != nil) + return err; + Fsconnected(c, nil); + + return nil; +} + +static void +grecreate(Conv *c) +{ + c->rq = qopen(64*1024, Qmsg, 0, c); + c->wq = qbypass(grekick, c); +} + +static int +grestate(Conv *c, char *state, int n) +{ + USED(c); + return snprint(state, n, "%s", "Datagram"); +} + +static char* +greannounce(Conv*, char**, int) +{ + return "pktifc does not support announce"; +} + +static void +greclose(Conv *c) +{ + qclose(c->rq); + qclose(c->wq); + qclose(c->eq); + ipmove(c->laddr, IPnoaddr); + ipmove(c->raddr, IPnoaddr); + c->lport = 0; + c->rport = 0; +} + +int drop; + +static void +grekick(void *x, Block *bp) +{ + Conv *c = x; + GREhdr *ghp; + uchar laddr[IPaddrlen], raddr[IPaddrlen]; + + if(bp == nil) + return; + + /* Make space to fit ip header (gre header already there) */ + bp = padblock(bp, GRE_IPONLY); + if(bp == nil) + return; + + /* make sure the message has a GRE header */ + bp = pullupblock(bp, GRE_IPONLY+GRE_IPPLUSGRE); + if(bp == nil) + return; + + ghp = (GREhdr *)(bp->rp); + ghp->vihl = IP_VER4; + + if(!((GREpriv*)c->p->priv)->raw){ + v4tov6(raddr, ghp->dst); + if(ipcmp(raddr, v4prefix) == 0) + memmove(ghp->dst, c->raddr + IPv4off, IPv4addrlen); + v4tov6(laddr, ghp->src); + if(ipcmp(laddr, v4prefix) == 0){ + if(ipcmp(c->laddr, IPnoaddr) == 0) + findlocalip(c->p->f, c->laddr, raddr); /* pick interface closest to dest */ + memmove(ghp->src, c->laddr + IPv4off, IPv4addrlen); + } + hnputs(ghp->eproto, c->rport); + } + + ghp->proto = IP_GREPROTO; + ghp->frag[0] = 0; + ghp->frag[1] = 0; + + ipoput4(c->p->f, bp, 0, c->ttl, c->tos, nil); +} + +static void +greiput(Proto *gre, Ipifc*, Block *bp) +{ + int len; + GREhdr *ghp; + Conv *c, **p; + ushort eproto; + uchar raddr[IPaddrlen]; + GREpriv *gpriv; + + gpriv = gre->priv; + ghp = (GREhdr*)(bp->rp); + + v4tov6(raddr, ghp->src); + eproto = nhgets(ghp->eproto); + qlock(gre); + + /* Look for a conversation structure for this port and address */ + c = nil; + for(p = gre->conv; *p; p++) { + c = *p; + if(c->inuse == 0) + continue; + if(c->rport == eproto && + (gpriv->raw || ipcmp(c->raddr, raddr) == 0)) + break; + } + + if(*p == nil) { + qunlock(gre); + freeblist(bp); + return; + } + + qunlock(gre); + + /* + * Trim the packet down to data size + */ + len = nhgets(ghp->len) - GRE_IPONLY; + if(len < GRE_IPPLUSGRE){ + freeblist(bp); + return; + } + bp = trimblock(bp, GRE_IPONLY, len); + if(bp == nil){ + gpriv->lenerr++; + return; + } + + /* + * Can't delimit packet so pull it all into one block. + */ + if(qlen(c->rq) > 64*1024) + freeblist(bp); + else{ + bp = concatblock(bp); + if(bp == 0) + panic("greiput"); + qpass(c->rq, bp); + } +} + +int +grestats(Proto *gre, char *buf, int len) +{ + GREpriv *gpriv; + + gpriv = gre->priv; + + return snprint(buf, len, "gre: len %lud\n", gpriv->lenerr); +} + +char* +grectl(Conv *c, char **f, int n) +{ + GREpriv *gpriv; + + gpriv = c->p->priv; + if(n == 1){ + if(strcmp(f[0], "raw") == 0){ + gpriv->raw = 1; + return nil; + } + else if(strcmp(f[0], "cooked") == 0){ + gpriv->raw = 0; + return nil; + } + } + return "unknown control request"; +} + +void +greinit(Fs *fs) +{ + Proto *gre; + + gre = smalloc(sizeof(Proto)); + gre->priv = smalloc(sizeof(GREpriv)); + gre->name = "gre"; + gre->connect = greconnect; + gre->announce = greannounce; + gre->state = grestate; + gre->create = grecreate; + gre->close = greclose; + gre->rcv = greiput; + gre->ctl = grectl; + gre->advise = nil; + gre->stats = grestats; + gre->ipproto = IP_GREPROTO; + gre->nc = 64; + gre->ptclsize = 0; + + Fsproto(fs, gre); +} |