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-rw-r--r--libc-top-half/musl/src/network/lookup_name.c425
1 files changed, 425 insertions, 0 deletions
diff --git a/libc-top-half/musl/src/network/lookup_name.c b/libc-top-half/musl/src/network/lookup_name.c
new file mode 100644
index 0000000..aa558c1
--- /dev/null
+++ b/libc-top-half/musl/src/network/lookup_name.c
@@ -0,0 +1,425 @@
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netdb.h>
+#include <net/if.h>
+#include <arpa/inet.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <pthread.h>
+#include <errno.h>
+#include <resolv.h>
+#include "lookup.h"
+#include "stdio_impl.h"
+#include "syscall.h"
+
+static int is_valid_hostname(const char *host)
+{
+ const unsigned char *s;
+ if (strnlen(host, 255)-1 >= 254 || mbstowcs(0, host, 0) == -1) return 0;
+ for (s=(void *)host; *s>=0x80 || *s=='.' || *s=='-' || isalnum(*s); s++);
+ return !*s;
+}
+
+static int name_from_null(struct address buf[static 2], const char *name, int family, int flags)
+{
+ int cnt = 0;
+ if (name) return 0;
+ if (flags & AI_PASSIVE) {
+ if (family != AF_INET6)
+ buf[cnt++] = (struct address){ .family = AF_INET };
+ if (family != AF_INET)
+ buf[cnt++] = (struct address){ .family = AF_INET6 };
+ } else {
+ if (family != AF_INET6)
+ buf[cnt++] = (struct address){ .family = AF_INET, .addr = { 127,0,0,1 } };
+ if (family != AF_INET)
+ buf[cnt++] = (struct address){ .family = AF_INET6, .addr = { [15] = 1 } };
+ }
+ return cnt;
+}
+
+static int name_from_numeric(struct address buf[static 1], const char *name, int family)
+{
+ return __lookup_ipliteral(buf, name, family);
+}
+
+static int name_from_hosts(struct address buf[static MAXADDRS], char canon[static 256], const char *name, int family)
+{
+ char line[512];
+ size_t l = strlen(name);
+ int cnt = 0, badfam = 0, have_canon = 0;
+ unsigned char _buf[1032];
+ FILE _f, *f = __fopen_rb_ca("/etc/hosts", &_f, _buf, sizeof _buf);
+ if (!f) switch (errno) {
+ case ENOENT:
+ case ENOTDIR:
+ case EACCES:
+ return 0;
+ default:
+ return EAI_SYSTEM;
+ }
+ while (fgets(line, sizeof line, f) && cnt < MAXADDRS) {
+ char *p, *z;
+
+ if ((p=strchr(line, '#'))) *p++='\n', *p=0;
+ for(p=line+1; (p=strstr(p, name)) &&
+ (!isspace(p[-1]) || !isspace(p[l])); p++);
+ if (!p) continue;
+
+ /* Isolate IP address to parse */
+ for (p=line; *p && !isspace(*p); p++);
+ *p++ = 0;
+ switch (name_from_numeric(buf+cnt, line, family)) {
+ case 1:
+ cnt++;
+ break;
+ case 0:
+ continue;
+ default:
+ badfam = EAI_NONAME;
+ break;
+ }
+
+ if (have_canon) continue;
+
+ /* Extract first name as canonical name */
+ for (; *p && isspace(*p); p++);
+ for (z=p; *z && !isspace(*z); z++);
+ *z = 0;
+ if (is_valid_hostname(p)) {
+ have_canon = 1;
+ memcpy(canon, p, z-p+1);
+ }
+ }
+ __fclose_ca(f);
+ return cnt ? cnt : badfam;
+}
+
+struct dpc_ctx {
+ struct address *addrs;
+ char *canon;
+ int cnt;
+};
+
+#define RR_A 1
+#define RR_CNAME 5
+#define RR_AAAA 28
+
+static int dns_parse_callback(void *c, int rr, const void *data, int len, const void *packet)
+{
+ char tmp[256];
+ struct dpc_ctx *ctx = c;
+ if (ctx->cnt >= MAXADDRS) return -1;
+ switch (rr) {
+ case RR_A:
+ if (len != 4) return -1;
+ ctx->addrs[ctx->cnt].family = AF_INET;
+ ctx->addrs[ctx->cnt].scopeid = 0;
+ memcpy(ctx->addrs[ctx->cnt++].addr, data, 4);
+ break;
+ case RR_AAAA:
+ if (len != 16) return -1;
+ ctx->addrs[ctx->cnt].family = AF_INET6;
+ ctx->addrs[ctx->cnt].scopeid = 0;
+ memcpy(ctx->addrs[ctx->cnt++].addr, data, 16);
+ break;
+ case RR_CNAME:
+ if (__dn_expand(packet, (const unsigned char *)packet + 512,
+ data, tmp, sizeof tmp) > 0 && is_valid_hostname(tmp))
+ strcpy(ctx->canon, tmp);
+ break;
+ }
+ return 0;
+}
+
+static int name_from_dns(struct address buf[static MAXADDRS], char canon[static 256], const char *name, int family, const struct resolvconf *conf)
+{
+ unsigned char qbuf[2][280], abuf[2][512];
+ const unsigned char *qp[2] = { qbuf[0], qbuf[1] };
+ unsigned char *ap[2] = { abuf[0], abuf[1] };
+ int qlens[2], alens[2];
+ int i, nq = 0;
+ struct dpc_ctx ctx = { .addrs = buf, .canon = canon };
+ static const struct { int af; int rr; } afrr[2] = {
+ { .af = AF_INET6, .rr = RR_A },
+ { .af = AF_INET, .rr = RR_AAAA },
+ };
+
+ for (i=0; i<2; i++) {
+ if (family != afrr[i].af) {
+ qlens[nq] = __res_mkquery(0, name, 1, afrr[i].rr,
+ 0, 0, 0, qbuf[nq], sizeof *qbuf);
+ if (qlens[nq] == -1)
+ return EAI_NONAME;
+ qbuf[nq][3] = 0; /* don't need AD flag */
+ nq++;
+ }
+ }
+
+ if (__res_msend_rc(nq, qp, qlens, ap, alens, sizeof *abuf, conf) < 0)
+ return EAI_SYSTEM;
+
+ for (i=0; i<nq; i++) {
+ if (alens[i] < 4 || (abuf[i][3] & 15) == 2) return EAI_AGAIN;
+ if ((abuf[i][3] & 15) == 3) return 0;
+ if ((abuf[i][3] & 15) != 0) return EAI_FAIL;
+ }
+
+ for (i=0; i<nq; i++)
+ __dns_parse(abuf[i], alens[i], dns_parse_callback, &ctx);
+
+ if (ctx.cnt) return ctx.cnt;
+ return EAI_NONAME;
+}
+
+static int name_from_dns_search(struct address buf[static MAXADDRS], char canon[static 256], const char *name, int family)
+{
+ char search[256];
+ struct resolvconf conf;
+ size_t l, dots;
+ char *p, *z;
+
+ if (__get_resolv_conf(&conf, search, sizeof search) < 0) return -1;
+
+ /* Count dots, suppress search when >=ndots or name ends in
+ * a dot, which is an explicit request for global scope. */
+ for (dots=l=0; name[l]; l++) if (name[l]=='.') dots++;
+ if (dots >= conf.ndots || name[l-1]=='.') *search = 0;
+
+ /* Strip final dot for canon, fail if multiple trailing dots. */
+ if (name[l-1]=='.') l--;
+ if (!l || name[l-1]=='.') return EAI_NONAME;
+
+ /* This can never happen; the caller already checked length. */
+ if (l >= 256) return EAI_NONAME;
+
+ /* Name with search domain appended is setup in canon[]. This both
+ * provides the desired default canonical name (if the requested
+ * name is not a CNAME record) and serves as a buffer for passing
+ * the full requested name to name_from_dns. */
+ memcpy(canon, name, l);
+ canon[l] = '.';
+
+ for (p=search; *p; p=z) {
+ for (; isspace(*p); p++);
+ for (z=p; *z && !isspace(*z); z++);
+ if (z==p) break;
+ if (z-p < 256 - l - 1) {
+ memcpy(canon+l+1, p, z-p);
+ canon[z-p+1+l] = 0;
+ int cnt = name_from_dns(buf, canon, canon, family, &conf);
+ if (cnt) return cnt;
+ }
+ }
+
+ canon[l] = 0;
+ return name_from_dns(buf, canon, name, family, &conf);
+}
+
+static const struct policy {
+ unsigned char addr[16];
+ unsigned char len, mask;
+ unsigned char prec, label;
+} defpolicy[] = {
+ { "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\1", 15, 0xff, 50, 0 },
+ { "\0\0\0\0\0\0\0\0\0\0\xff\xff", 11, 0xff, 35, 4 },
+ { "\x20\2", 1, 0xff, 30, 2 },
+ { "\x20\1", 3, 0xff, 5, 5 },
+ { "\xfc", 0, 0xfe, 3, 13 },
+#if 0
+ /* These are deprecated and/or returned to the address
+ * pool, so despite the RFC, treating them as special
+ * is probably wrong. */
+ { "", 11, 0xff, 1, 3 },
+ { "\xfe\xc0", 1, 0xc0, 1, 11 },
+ { "\x3f\xfe", 1, 0xff, 1, 12 },
+#endif
+ /* Last rule must match all addresses to stop loop. */
+ { "", 0, 0, 40, 1 },
+};
+
+static const struct policy *policyof(const struct in6_addr *a)
+{
+ int i;
+ for (i=0; ; i++) {
+ if (memcmp(a->s6_addr, defpolicy[i].addr, defpolicy[i].len))
+ continue;
+ if ((a->s6_addr[defpolicy[i].len] & defpolicy[i].mask)
+ != defpolicy[i].addr[defpolicy[i].len])
+ continue;
+ return defpolicy+i;
+ }
+}
+
+static int labelof(const struct in6_addr *a)
+{
+ return policyof(a)->label;
+}
+
+static int scopeof(const struct in6_addr *a)
+{
+ if (IN6_IS_ADDR_MULTICAST(a)) return a->s6_addr[1] & 15;
+ if (IN6_IS_ADDR_LINKLOCAL(a)) return 2;
+ if (IN6_IS_ADDR_LOOPBACK(a)) return 2;
+ if (IN6_IS_ADDR_SITELOCAL(a)) return 5;
+ return 14;
+}
+
+static int prefixmatch(const struct in6_addr *s, const struct in6_addr *d)
+{
+ /* FIXME: The common prefix length should be limited to no greater
+ * than the nominal length of the prefix portion of the source
+ * address. However the definition of the source prefix length is
+ * not clear and thus this limiting is not yet implemented. */
+ unsigned i;
+ for (i=0; i<128 && !((s->s6_addr[i/8]^d->s6_addr[i/8])&(128>>(i%8))); i++);
+ return i;
+}
+
+#define DAS_USABLE 0x40000000
+#define DAS_MATCHINGSCOPE 0x20000000
+#define DAS_MATCHINGLABEL 0x10000000
+#define DAS_PREC_SHIFT 20
+#define DAS_SCOPE_SHIFT 16
+#define DAS_PREFIX_SHIFT 8
+#define DAS_ORDER_SHIFT 0
+
+static int addrcmp(const void *_a, const void *_b)
+{
+ const struct address *a = _a, *b = _b;
+ return b->sortkey - a->sortkey;
+}
+
+int __lookup_name(struct address buf[static MAXADDRS], char canon[static 256], const char *name, int family, int flags)
+{
+ int cnt = 0, i, j;
+
+ *canon = 0;
+ if (name) {
+ /* reject empty name and check len so it fits into temp bufs */
+ size_t l = strnlen(name, 255);
+ if (l-1 >= 254)
+ return EAI_NONAME;
+ memcpy(canon, name, l+1);
+ }
+
+ /* Procedurally, a request for v6 addresses with the v4-mapped
+ * flag set is like a request for unspecified family, followed
+ * by filtering of the results. */
+ if (flags & AI_V4MAPPED) {
+ if (family == AF_INET6) family = AF_UNSPEC;
+ else flags -= AI_V4MAPPED;
+ }
+
+ /* Try each backend until there's at least one result. */
+ cnt = name_from_null(buf, name, family, flags);
+ if (!cnt) cnt = name_from_numeric(buf, name, family);
+ if (!cnt && !(flags & AI_NUMERICHOST)) {
+ cnt = name_from_hosts(buf, canon, name, family);
+ if (!cnt) cnt = name_from_dns_search(buf, canon, name, family);
+ }
+ if (cnt<=0) return cnt ? cnt : EAI_NONAME;
+
+ /* Filter/transform results for v4-mapped lookup, if requested. */
+ if (flags & AI_V4MAPPED) {
+ if (!(flags & AI_ALL)) {
+ /* If any v6 results exist, remove v4 results. */
+ for (i=0; i<cnt && buf[i].family != AF_INET6; i++);
+ if (i<cnt) {
+ for (j=0; i<cnt; i++) {
+ if (buf[i].family == AF_INET6)
+ buf[j++] = buf[i];
+ }
+ cnt = i = j;
+ }
+ }
+ /* Translate any remaining v4 results to v6 */
+ for (i=0; i<cnt; i++) {
+ if (buf[i].family != AF_INET) continue;
+ memcpy(buf[i].addr+12, buf[i].addr, 4);
+ memcpy(buf[i].addr, "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12);
+ buf[i].family = AF_INET6;
+ }
+ }
+
+ /* No further processing is needed if there are fewer than 2
+ * results or if there are only IPv4 results. */
+ if (cnt<2 || family==AF_INET) return cnt;
+ for (i=0; i<cnt; i++) if (buf[i].family != AF_INET) break;
+ if (i==cnt) return cnt;
+
+ int cs;
+ pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
+
+ /* The following implements a subset of RFC 3484/6724 destination
+ * address selection by generating a single 31-bit sort key for
+ * each address. Rules 3, 4, and 7 are omitted for having
+ * excessive runtime and code size cost and dubious benefit.
+ * So far the label/precedence table cannot be customized. */
+ for (i=0; i<cnt; i++) {
+ int family = buf[i].family;
+ int key = 0;
+ struct sockaddr_in6 sa6 = { 0 }, da6 = {
+ .sin6_family = AF_INET6,
+ .sin6_scope_id = buf[i].scopeid,
+ .sin6_port = 65535
+ };
+ struct sockaddr_in sa4 = { 0 }, da4 = {
+ .sin_family = AF_INET,
+ .sin_port = 65535
+ };
+ void *sa, *da;
+ socklen_t salen, dalen;
+ if (family == AF_INET6) {
+ memcpy(da6.sin6_addr.s6_addr, buf[i].addr, 16);
+ da = &da6; dalen = sizeof da6;
+ sa = &sa6; salen = sizeof sa6;
+ } else {
+ memcpy(sa6.sin6_addr.s6_addr,
+ "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12);
+ memcpy(da6.sin6_addr.s6_addr+12, buf[i].addr, 4);
+ memcpy(da6.sin6_addr.s6_addr,
+ "\0\0\0\0\0\0\0\0\0\0\xff\xff", 12);
+ memcpy(da6.sin6_addr.s6_addr+12, buf[i].addr, 4);
+ memcpy(&da4.sin_addr, buf[i].addr, 4);
+ da = &da4; dalen = sizeof da4;
+ sa = &sa4; salen = sizeof sa4;
+ }
+ const struct policy *dpolicy = policyof(&da6.sin6_addr);
+ int dscope = scopeof(&da6.sin6_addr);
+ int dlabel = dpolicy->label;
+ int dprec = dpolicy->prec;
+ int prefixlen = 0;
+ int fd = socket(family, SOCK_DGRAM|SOCK_CLOEXEC, IPPROTO_UDP);
+ if (fd >= 0) {
+ if (!connect(fd, da, dalen)) {
+ key |= DAS_USABLE;
+ if (!getsockname(fd, sa, &salen)) {
+ if (family == AF_INET) memcpy(
+ sa6.sin6_addr.s6_addr+12,
+ &sa4.sin_addr, 4);
+ if (dscope == scopeof(&sa6.sin6_addr))
+ key |= DAS_MATCHINGSCOPE;
+ if (dlabel == labelof(&sa6.sin6_addr))
+ key |= DAS_MATCHINGLABEL;
+ prefixlen = prefixmatch(&sa6.sin6_addr,
+ &da6.sin6_addr);
+ }
+ }
+ close(fd);
+ }
+ key |= dprec << DAS_PREC_SHIFT;
+ key |= (15-dscope) << DAS_SCOPE_SHIFT;
+ key |= prefixlen << DAS_PREFIX_SHIFT;
+ key |= (MAXADDRS-i) << DAS_ORDER_SHIFT;
+ buf[i].sortkey = key;
+ }
+ qsort(buf, cnt, sizeof *buf, addrcmp);
+
+ pthread_setcancelstate(cs, 0);
+
+ return cnt;
+}
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