Index: fusl/src/network/dn_comp.c |
diff --git a/fusl/src/network/dn_comp.c b/fusl/src/network/dn_comp.c |
new file mode 100644 |
index 0000000000000000000000000000000000000000..a17d434dc260abcf8aaf15175d7ef28b0a8a9245 |
--- /dev/null |
+++ b/fusl/src/network/dn_comp.c |
@@ -0,0 +1,110 @@ |
+#include <string.h> |
+#include <resolv.h> |
+#include "libc.h" |
+ |
+/* RFC 1035 message compression */ |
+ |
+/* label start offsets of a compressed domain name s */ |
+static int getoffs(short *offs, const unsigned char *base, const unsigned char *s) |
+{ |
+ int i=0; |
+ for (;;) { |
+ while (*s & 0xc0) { |
+ if ((*s & 0xc0) != 0xc0) return 0; |
+ s = base + ((s[0]&0x3f)<<8 | s[1]); |
+ } |
+ if (!*s) return i; |
+ if (s-base >= 0x4000) return 0; |
+ offs[i++] = s-base; |
+ s += *s + 1; |
+ } |
+} |
+ |
+/* label lengths of an ascii domain name s */ |
+static int getlens(unsigned char *lens, const char *s, int l) |
+{ |
+ int i=0,j=0,k=0; |
+ for (;;) { |
+ for (; j<l && s[j]!='.'; j++); |
+ if (j-k-1u > 62) return 0; |
+ lens[i++] = j-k; |
+ if (j==l) return i; |
+ k = ++j; |
+ } |
+} |
+ |
+/* longest suffix match of an ascii domain with a compressed domain name dn */ |
+static int match(int *offset, const unsigned char *base, const unsigned char *dn, |
+ const char *end, const unsigned char *lens, int nlen) |
+{ |
+ int l, o, m=0; |
+ short offs[128]; |
+ int noff = getoffs(offs, base, dn); |
+ if (!noff) return 0; |
+ for (;;) { |
+ l = lens[--nlen]; |
+ o = offs[--noff]; |
+ end -= l; |
+ if (l != base[o] || memcmp(base+o+1, end, l)) |
+ return m; |
+ *offset = o; |
+ m += l; |
+ if (nlen) m++; |
+ if (!nlen || !noff) return m; |
+ end--; |
+ } |
+} |
+ |
+int __dn_comp(const char *src, unsigned char *dst, int space, unsigned char **dnptrs, unsigned char **lastdnptr) |
+{ |
+ int i, j, n, m=0, offset, bestlen=0, bestoff; |
+ unsigned char lens[127]; |
+ unsigned char **p; |
+ const char *end; |
+ size_t l = strnlen(src, 255); |
+ if (l && src[l-1] == '.') l--; |
+ if (l>253 || space<=0) return -1; |
+ if (!l) { |
+ *dst = 0; |
+ return 1; |
+ } |
+ end = src+l; |
+ n = getlens(lens, src, l); |
+ if (!n) return -1; |
+ |
+ p = dnptrs; |
+ if (p && *p) for (p++; *p; p++) { |
+ m = match(&offset, *dnptrs, *p, end, lens, n); |
+ if (m > bestlen) { |
+ bestlen = m; |
+ bestoff = offset; |
+ if (m == l) |
+ break; |
+ } |
+ } |
+ |
+ /* encode unmatched part */ |
+ if (space < l-bestlen+2+(bestlen-1 < l-1)) return -1; |
+ memcpy(dst+1, src, l-bestlen); |
+ for (i=j=0; i<l-bestlen; i+=lens[j++]+1) |
+ dst[i] = lens[j]; |
+ |
+ /* add tail */ |
+ if (bestlen) { |
+ dst[i++] = 0xc0 | bestoff>>8; |
+ dst[i++] = bestoff; |
+ } else |
+ dst[i++] = 0; |
+ |
+ /* save dst pointer */ |
+ if (i>2 && lastdnptr && dnptrs && *dnptrs) { |
+ while (*p) p++; |
+ if (p+1 < lastdnptr) { |
+ *p++ = dst; |
+ *p=0; |
+ } |
+ } |
+ return i; |
+} |
+ |
+weak_alias(__dn_comp, dn_comp); |