/* * DNS referrals give two main fields: the path to connect to in * /Netbios-host-name/share-name/path... form and a network * address of how to find this path of the form domain.dom. * * The domain.dom is resolved in XP/Win2k etc using AD to do * a lookup (this is a consensus view, I don't think anyone * has proved it). I cannot do this as AD needs Kerberos and * LDAP which I don't have. * * Instead I just use the NetBios names passed in the paths * and assume that the servers are in the same DNS domain as me * and have their DNS hostname set the same as their netbios * called-name; thankfully this always seems to be the case (so far). * * I have not added support for starting another instance of * cifs to connect to other servers referenced in DFS links, * this is not a problem for me and I think it hides a load * of problems of its own wrt plan9's private namespaces. * * The proximity of my test server (AD enabled) is always 0 but some * systems may report more meaningful values. The expiry time is * similarly zero, so I guess at 5 mins. * * If the redirection points to a "hidden" share (i.e., its name * ends in a $) then the type of the redirection is 0 (unknown) even * though it is a CIFS share. * * It would be nice to add a check for which subnet a server is on * so our first choice is always the the server on the same subnet * as us which replies to a ping (i.e., is up). This could short- * circuit the tests as the a server on the same subnet will always * be the fastest to get to. * * If I set Flags2_DFS then I don't see DFS links, I just get * path not found (?!). * * If I do a QueryFileInfo of a DFS link point (IE when I'am doing a walk) * Then I just see a directory, its not until I try to walk another level * That I get "IO reparse tag not handled" error rather than * "Path not covered". * * If I check the extended attributes of the QueryFileInfo in walk() then I can * see this is a reparse point and so I can get the referral. The only * problem here is that samba and the like may not support this. */ #include #include #include #include #include #include #include <9p.h> #include "cifs.h" #define SINT_MAX 0x7fffffff typedef struct Dfscache Dfscache; struct Dfscache { Dfscache*next; /* next entry */ char *src; char *host; char *share; char *path; long expiry; /* expiry time in sec */ long rtt; /* round trip time, nsec */ int prox; /* proximity, lower = closer */ }; Dfscache *Cache; int dfscacheinfo(Fmt *f) { long ex; Dfscache *cp; for(cp = Cache; cp; cp = cp->next){ ex = cp->expiry - time(nil); if(ex < 0) ex = -1; fmtprint(f, "%-42s %6ld %8.1f %4d %-16s %-24s %s\n", cp->src, ex, (double)cp->rtt/1000.0L, cp->prox, cp->host, cp->share, cp->path); } return 0; } char * trimshare(char *s) { char *p; static char name[128]; strncpy(name, s, sizeof(name)); name[sizeof(name)-1] = 0; if((p = strrchr(name, '$')) != nil && p[1] == 0) *p = 0; return name; } static Dfscache * lookup(char *opath, int *exact) { char *path; int len, n, m; Dfscache *cp, *best; *exact = 0; len = 0; best = nil; path = opath; m = strlen(opath); for(cp = Cache; cp; cp = cp->next){ n = strlen(cp->src); if(n < len || cistrncmp(path, cp->src, n) != 0 || path[n] != 0 && path[n] != '/') continue; best = cp; len = n; if(n == m){ *exact = 1; break; } } return best; } char * mapfile(char *opath) { int exact; char *p, *path; Dfscache *cp; static char npath[MAX_DFS_PATH]; path = opath; if((cp = lookup(path, &exact)) != nil){ snprint(npath, sizeof npath, "/%s%s%s%s", cp->share, *cp->path? "/": "", cp->path, path + strlen(cp->src)); path = npath; } if((p = strchr(path+1, '/')) == nil) p = "/"; if(Debug && strstr(Debug, "dfs") != nil) print("mapfile src=%q => dst=%q\n", opath, p); return p; } int mapshare(char *path, Share **osp) { int i, exact; char *try, *tail[] = { "", "$" }; Dfscache *cp; Share *sp; if((cp = lookup(path, &exact)) == nil) return 0; for(sp = Shares; sp < Shares+Nshares; sp++) if(cistrcmp(cp->share, trimshare(sp->name)) == 0){ if(Debug && strstr(Debug, "dfs") != nil) print("mapshare, already connected, src=%q => dst=%q\n", path, sp->name); *osp = sp; return 0; } /* * Try to autoconnect to share if it is not known. Note even if you * didn't specify any shares and let the system autoconnect you may * not already have the share you need as RAP (which we use) throws * away names > 12 chars long. If we where to use RPC then this block * of code would be less important, though it would still be useful * to catch Shares added since cifs(1) was started. */ sp = Shares + Nshares; for(i = 0; i < 2; i++){ try = smprint("%s%s", cp->share, tail[i]); if(CIFStreeconnect(Sess, Sess->cname, try, sp) == 0){ sp->name = try; *osp = sp; Nshares++; if(Debug && strstr(Debug, "dfs") != nil) print("mapshare connected, src=%q dst=%q\n", path, cp->share); return 0; } free(try); } if(Debug && strstr(Debug, "dfs") != nil) print("mapshare failed src=%s\n", path); return -1; } /* * Rtt_tol is the fractional tollerance for RTT comparisons. * If a later (further down the list) host's RTT is less than * 1/Rtt_tol better than my current best then I don't bother * with it. This biases me towards entries at the top of the list * which Active Directory has already chosen for me and prevents * noise in RTTs from pushing me to more distant machines. */ static int remap(Dfscache *cp, Refer *re) { int n; long rtt; char *p, *a[4]; enum { Hostname = 1, Shre = 2, Path = 3, Rtt_tol = 10, }; if(Debug && strstr(Debug, "dfs") != nil) print(" remap %s\n", re->addr); for(p = re->addr; *p; p++) if(*p == '\\') *p = '/'; if(cp->prox < re->prox){ if(Debug && strstr(Debug, "dfs") != nil) print(" remap %d < %d\n", cp->prox, re->prox); return -1; } if((n = getfields(re->addr, a, sizeof(a), 0, "/")) < 3){ if(Debug && strstr(Debug, "dfs") != nil) print(" remap nfields=%d\n", n); return -1; } if((rtt = ping(a[Hostname], Dfstout)) == -1){ if(Debug && strstr(Debug, "dfs") != nil) print(" remap ping failed\n"); return -1; } if(cp->rtt < rtt && (rtt/labs(rtt-cp->rtt)) < Rtt_tol){ if(Debug && strstr(Debug, "dfs") != nil) print(" remap bad ping %ld < %ld && %ld < %d\n", cp->rtt, rtt, (rtt/labs(rtt-cp->rtt)), Rtt_tol); return -1; } if(n < 4) a[Path] = ""; if(re->ttl == 0) re->ttl = 60*5; free(cp->host); free(cp->share); free(cp->path); cp->rtt = rtt; cp->prox = re->prox; cp->expiry = time(nil)+re->ttl; cp->host = estrdup9p(a[Hostname]); cp->share = estrdup9p(trimshare(a[Shre])); cp->path = estrdup9p(a[Path]); if(Debug && strstr(Debug, "dfs") != nil) print(" remap ping OK prox=%d host=%s share=%s path=%s\n", cp->prox, cp->host, cp->share, cp->path); return 0; } static int redir1(Session *s, char *path, Dfscache *cp, int level) { Refer retab[16], *re; int n, gflags, used, found; if(level > 8) return -1; if((n = T2getdfsreferral(s, &Ipc, path, &gflags, &used, retab, nelem(retab))) == -1) return -1; if(! (gflags & DFS_HEADER_ROOT)) used = SINT_MAX; found = 0; for(re = retab; re < retab+n; re++){ if(Debug && strstr(Debug, "dfs") != nil) print("referal level=%d prox=%d path=%q addr=%q\n", level, re->prox, re->path, re->addr); if(gflags & DFS_HEADER_STORAGE){ if(remap(cp, re) == 0) found = 1; } else{ if(redir1(s, re->addr, cp, level+1) != -1) /* ???? */ found = 1; } free(re->addr); free(re->path); } if(Debug && strstr(Debug, "dfs") != nil) print("referal level=%d path=%q found=%d used=%d\n", level, path, found, used); if(!found) return -1; return used; } /* * We can afford to ignore the used count returned by redir * because of the semantics of 9p - we always walk to directories * ome and we a time and we always walk before any other file operations */ int redirect(Session *s, Share *sp, char *path) { int exact; char *unc; Dfscache *cp; if(Debug && strstr(Debug, "dfs") != nil) print("redirect name=%q path=%q\n", sp->name, path); cp = lookup(path, &exact); if(cp && exact){ if(cp->expiry >= time(nil)){ /* cache hit */ if(Debug && strstr(Debug, "dfs") != nil) print("redirect cache=hit src=%q => share=%q path=%q\n", cp->src, cp->share, cp->path); return 0; } else{ /* cache hit, but entry stale */ cp->rtt = SINT_MAX; cp->prox = SINT_MAX; unc = smprint("//%s/%s/%s%s%s", s->auth->windom, cp->share, cp->path, *cp->path? "/": "", path + strlen(cp->src) + 1); if(unc == nil) sysfatal("no memory: %r"); if(redir1(s, unc, cp, 1) == -1){ if(Debug && strstr(Debug, "dfs") != nil) print("redirect refresh failed unc=%q\n", unc); free(unc); return -1; } free(unc); if(Debug && strstr(Debug, "dfs") != nil) print("redirect refresh cache=stale src=%q => share=%q path=%q\n", cp->src, cp->share, cp->path); return 0; } } /* in-exact match or complete miss */ if(cp) unc = smprint("//%s/%s/%s%s%s", s->auth->windom, cp->share, cp->path, *cp->path? "/": "", path + strlen(cp->src) + 1); else unc = smprint("//%s%s", s->auth->windom, path); if(unc == nil) sysfatal("no memory: %r"); cp = emalloc9p(sizeof(Dfscache)); memset(cp, 0, sizeof(Dfscache)); cp->rtt = SINT_MAX; cp->prox = SINT_MAX; if(redir1(s, unc, cp, 1) == -1){ if(Debug && strstr(Debug, "dfs") != nil) print("redirect new failed unc=%q\n", unc); free(unc); free(cp); return -1; } free(unc); cp->src = estrdup9p(path); cp->next = Cache; Cache = cp; if(Debug && strstr(Debug, "dfs") != nil) print("redirect cache=miss src=%q => share=%q path=%q\n", cp->src, cp->share, cp->path); return 0; }