The new DNS API abstracts away differences between the gethostbyname-
and getaddrinfo-centric interfaces for looking up a host, making the
code to use them in connect.c a little easier to read.
To make a lookup:
resolver_result ai;
dns_resolve(host, port, 0, &ai);
...
dns_free(ai);
To iterate over responses:
resolved_address i;
for_each_address(i, ai) {
...
}
In the !NO_IPV6 codepath, the git_locate_host function used to find
the canonical IP and hostname for a git server's public address (for
virtual hosting) tells getaddrinfo to restrict attention to TCP
services after this patch. That should make a difference because the
service parameter is NULL.
No functional change intended.
Signed-off-by: Jonathan Nieder <jrnieder@xxxxxxxxx>
---
Makefile | 5 ++
dns-ipv4.c | 33 +++++++++++
dns-ipv4.h | 65 ++++++++++++++++++++++
dns-ipv6.c | 45 +++++++++++++++
dns-ipv6.h | 31 ++++++++++
tcp.c | 180 +++++++++++-------------------------------------------------
6 files changed, 211 insertions(+), 148 deletions(-)
create mode 100644 dns-ipv4.c
create mode 100644 dns-ipv4.h
create mode 100644 dns-ipv6.c
create mode 100644 dns-ipv6.h
diff --git a/Makefile b/Makefile
index df84157..7d3cb41 100644
--- a/Makefile
+++ b/Makefile
@@ -1474,6 +1474,11 @@ ifdef NO_TRUSTABLE_FILEMODE
endif
ifdef NO_IPV6
BASIC_CFLAGS += -DNO_IPV6
+ LIB_OBJS += dns-ipv4.o
+ LIB_H += dns-ipv4.h
+else
+ LIB_OBJS += dns-ipv6.o
+ LIB_H += dns-ipv6.h
endif
ifdef NO_UINTMAX_T
BASIC_CFLAGS += -Duintmax_t=uint32_t
diff --git a/dns-ipv4.c b/dns-ipv4.c
new file mode 100644
index 0000000..39849c3
--- /dev/null
+++ b/dns-ipv4.c
@@ -0,0 +1,33 @@
+#include "cache.h"
+#include "dns-ipv4.h"
+
+int dns_resolve(const char *host, const char *port, int flags,
+ resolver_result *res)
+{
+ char *ep;
+ struct hostent *he;
+ unsigned int nport;
+
+ he = gethostbyname(host);
+ if (!he && (flags & RESOLVE_IGNORE_ERROR))
+ return -1;
+ if (!he)
+ die("Unable to look up %s (%s)", host, hstrerror(h_errno));
+
+ if (!port) {
+ nport = 0;
+ goto done;
+ }
+ nport = strtoul(port, &ep, 10);
+ if ( ep == port || *ep ) {
+ /* Not numeric */
+ struct servent *se = getservbyname(port,"tcp");
+ if ( !se )
+ die("Unknown port %s", port);
+ nport = se->s_port;
+ }
+done:
+ res->he = he;
+ res->port = nport;
+ return 0;
+}
diff --git a/dns-ipv4.h b/dns-ipv4.h
new file mode 100644
index 0000000..ef7208f
--- /dev/null
+++ b/dns-ipv4.h
@@ -0,0 +1,65 @@
+#ifndef DNS_IPV4_H
+#define DNS_IPV4_H
+
+struct ipv4_address {
+ char **ap;
+ struct sockaddr_in sa;
+};
+
+struct ipv4_addrinfo {
+ struct hostent *he;
+ unsigned int port;
+};
+
+typedef struct ipv4_addrinfo resolver_result;
+typedef struct ipv4_address resolved_address;
+
+enum {
+ RESOLVE_CANONNAME = 1,
+ RESOLVE_IGNORE_ERROR = 2
+};
+extern int dns_resolve(const char *host, const char *port, int flags,
+ resolver_result *res);
+
+static inline const char *dns_name(const resolved_address *addr)
+{
+ return inet_ntoa(*(struct in_addr *)&addr->sa.sin_addr);
+}
+
+static inline char *dns_ip_address(const resolved_address *addr,
+ const resolver_result *ai)
+{
+ char addrbuf[HOST_NAME_MAX + 1];
+ inet_ntop(ai->he->h_addrtype, &addr->sa.sin_addr,
+ addrbuf, sizeof(addrbuf));
+ return xstrdup(addrbuf);
+}
+
+static inline int dns_fill_sockaddr_(char *ap,
+ const struct ipv4_addrinfo *ai, struct sockaddr_in *sa)
+{
+ if (!ap) /* done. */
+ return -1;
+
+ memset(sa, 0, sizeof(*sa));
+ sa->sin_family = ai->he->h_addrtype;
+ sa->sin_port = htons(ai->port);
+ memcpy(&sa->sin_addr, ap, ai->he->h_length);
+ return 0;
+}
+
+#define for_each_address(addr, ai) \
+ for ((addr).ap = (ai).he->h_addr_list; \
+ !dns_fill_sockaddr_(*(addr).ap, &(ai), &(addr).sa); \
+ (addr).ap++)
+
+#define dns_family(addr, ai) ((ai).he->h_addrtype)
+#define dns_socktype(addr, ai) SOCK_STREAM
+#define dns_protocol(addr, ai) 0
+#define dns_addr(addr, ai) ((struct sockaddr *) &(addr).sa)
+#define dns_addrlen(addr, ai) sizeof((addr).sa)
+#define dns_canonname(addr, ai) ((ai).he->h_name)
+
+#define dns_free(ai) do { /* nothing */ } while (0)
+
+#endif
diff --git a/dns-ipv6.c b/dns-ipv6.c
new file mode 100644
index 0000000..b5f298a
--- /dev/null
+++ b/dns-ipv6.c
@@ -0,0 +1,45 @@
+#include "cache.h"
+#include "dns-ipv6.h"
+
+const char *dns_name(const resolved_address *i)
+{
+ const struct addrinfo *ai = *i;
+ static char addr[NI_MAXHOST];
+ if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
+ NI_NUMERICHOST) != 0)
+ strcpy(addr, "(unknown)");
+
+ return addr;
+}
+
+char *dns_ip_address(const resolved_address *i, const resolver_result *ai0)
+{
+ const struct addrinfo *ai = *i;
+ char addrbuf[HOST_NAME_MAX + 1];
+ struct sockaddr_in *sin_addr;
+
+ sin_addr = (void *)ai->ai_addr;
+ inet_ntop(AF_INET, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
+ return xstrdup(addrbuf);
+}
+
+int dns_resolve(const char *host, const char *port, int flags,
+ resolver_result *res)
+{
+ struct addrinfo hints;
+ int gai;
+
+ memset(&hints, 0, sizeof(hints));
+ if (flags & RESOLVE_CANONNAME)
+ hints.ai_flags = AI_CANONNAME;
+ hints.ai_socktype = SOCK_STREAM;
+ hints.ai_protocol = IPPROTO_TCP;
+
+ gai = getaddrinfo(host, port, &hints, res);
+ if (gai && (flags & RESOLVE_IGNORE_ERROR))
+ return -1;
+ if (gai)
+ die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
+
+ return 0;
+}
diff --git a/dns-ipv6.h b/dns-ipv6.h
new file mode 100644
index 0000000..339877f
--- /dev/null
+++ b/dns-ipv6.h
@@ -0,0 +1,31 @@
+#ifndef DNS_IPV6_H
+#define DNS_IPV6_H
+
+typedef struct addrinfo *resolver_result;
+typedef const struct addrinfo *resolved_address;
+
+enum {
+ RESOLVE_CANONNAME = 1,
+ RESOLVE_IGNORE_ERROR = 2
+};
+extern int dns_resolve(const char *host, const char *port, int flags,
+ resolver_result *res);
+/* result is in static buffer */
+extern const char *dns_name(const resolved_address *i);
+/* result is in malloc'ed buffer */
+extern char *dns_ip_address(const resolved_address *i,
+ const resolver_result *ai);
+
+#define for_each_address(i, ai) \
+ for (i = ai; i; i = (i)->ai_next)
+
+#define dns_family(i, ai) ((i)->ai_family)
+#define dns_socktype(i, ai) ((i)->ai_socktype)
+#define dns_protocol(i, ai) ((i)->ai_protocol)
+#define dns_addr(i, ai) ((i)->ai_addr)
+#define dns_addrlen(i, ai) ((i)->ai_addrlen)
+#define dns_canonname(i, ai) ((i)->ai_canonname)
+
+#define dns_free(ai) freeaddrinfo(ai)
+
+#endif
diff --git a/tcp.c b/tcp.c
index 9916272..aacc2d1 100644
--- a/tcp.c
+++ b/tcp.c
@@ -1,6 +1,12 @@
#include "cache.h"
#include "run-command.h"
+#ifndef NO_IPV6
+#include "dns-ipv6.h"
+#else
+#include "dns-ipv4.h"
+#endif
+
#define STR_(s) # s
#define STR(s) STR_(s)
@@ -85,44 +91,27 @@ static void get_host_and_port(char **host, const char **port)
}
}
-#ifndef NO_IPV6
-
-static const char *ai_name(const struct addrinfo *ai)
-{
- static char addr[NI_MAXHOST];
- if (getnameinfo(ai->ai_addr, ai->ai_addrlen, addr, sizeof(addr), NULL, 0,
- NI_NUMERICHOST) != 0)
- strcpy(addr, "(unknown)");
-
- return addr;
-}
-
void git_locate_host(const char *hostname, char **ip_address,
char **canon_hostname)
{
- struct addrinfo hints;
- struct addrinfo *ai;
- int gai;
- static char addrbuf[HOST_NAME_MAX + 1];
- struct sockaddr_in *sin_addr;
+ resolver_result ai;
+ resolved_address i;
- memset(&hints, 0, sizeof(hints));
- hints.ai_flags = AI_CANONNAME;
-
- gai = getaddrinfo(hostname, NULL, &hints, &ai);
- if (gai)
+ if (dns_resolve(hostname, NULL,
+ RESOLVE_CANONNAME | RESOLVE_IGNORE_ERROR, &ai))
return;
- sin_addr = (void *)ai->ai_addr;
- inet_ntop(AF_INET, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
- free(*ip_address);
- *ip_address = xstrdup(addrbuf);
+ for_each_address(i, ai) {
+ free(*ip_address);
+ *ip_address = dns_ip_address(&i, &ai);
- free(*canon_hostname);
- *canon_hostname = xstrdup(ai->ai_canonname ?
- ai->ai_canonname : *ip_address);
+ free(*canon_hostname);
+ *canon_hostname = xstrdup(dns_canonname(i, ai) ?
+ dns_canonname(i, ai) : *ip_address);
+ break;
+ }
- freeaddrinfo(ai);
+ dns_free(ai);
}
/*
@@ -132,52 +121,48 @@ static int git_tcp_connect_sock(char *host, int flags)
{
int sockfd = -1, saved_errno = 0;
const char *port = STR(DEFAULT_GIT_PORT);
- struct addrinfo hints, *ai0, *ai;
- int gai;
- int cnt;
+ resolver_result ai;
+ resolved_address i;
+ int cnt = -1;
get_host_and_port(&host, &port);
if (!*port)
port = "<none>";
- memset(&hints, 0, sizeof(hints));
- hints.ai_socktype = SOCK_STREAM;
- hints.ai_protocol = IPPROTO_TCP;
-
if (flags & CONNECT_VERBOSE)
fprintf(stderr, "Looking up %s ... ", host);
- gai = getaddrinfo(host, port, &hints, &ai);
- if (gai)
- die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
+ if (dns_resolve(host, port, 0, &ai))
+ die("BUG: dns_resolve returned error?");
if (flags & CONNECT_VERBOSE)
fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
- for (cnt = 0, ai0 = ai; ai; ai = ai->ai_next, cnt++) {
- sockfd = socket(ai->ai_family,
- ai->ai_socktype, ai->ai_protocol);
+ for_each_address(i, ai) {
+ cnt++;
+ sockfd = socket(dns_family(i, ai),
+ dns_socktype(i, ai), dns_protocol(i, ai));
if (sockfd < 0) {
saved_errno = errno;
continue;
}
- if (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
+ if (connect(sockfd, dns_addr(i, ai), dns_addrlen(i, ai)) < 0) {
saved_errno = errno;
fprintf(stderr, "%s[%d: %s]: errno=%s\n",
host,
cnt,
- ai_name(ai),
+ dns_name(&i),
strerror(saved_errno));
close(sockfd);
sockfd = -1;
continue;
}
if (flags & CONNECT_VERBOSE)
- fprintf(stderr, "%s ", ai_name(ai));
+ fprintf(stderr, "%s ", dns_name(&i));
break;
}
- freeaddrinfo(ai0);
+ dns_free(ai);
if (sockfd < 0)
die("unable to connect a socket (%s)", strerror(saved_errno));
@@ -188,107 +173,6 @@ static int git_tcp_connect_sock(char *host, int flags)
return sockfd;
}
-#else /* NO_IPV6 */
-
-void git_locate_host(const char *hostname, char **ip_address,
- char **canon_hostname)
-{
- struct hostent *hent;
- struct sockaddr_in sa;
- char **ap;
- static char addrbuf[HOST_NAME_MAX + 1];
-
- hent = gethostbyname(hostname);
-
- ap = hent->h_addr_list;
- memset(&sa, 0, sizeof sa);
- sa.sin_family = hent->h_addrtype;
- sa.sin_port = htons(0);
- memcpy(&sa.sin_addr, *ap, hent->h_length);
-
- inet_ntop(hent->h_addrtype, &sa.sin_addr,
- addrbuf, sizeof(addrbuf));
-
- free(*canon_hostname);
- *canon_hostname = xstrdup(hent->h_name);
- free(*ip_address);
- *ip_address = xstrdup(addrbuf);
-}
-
-/*
- * Returns a connected socket() fd, or else die()s.
- */
-static int git_tcp_connect_sock(char *host, int flags)
-{
- int sockfd = -1, saved_errno = 0;
- const char *port = STR(DEFAULT_GIT_PORT);
- char *ep;
- struct hostent *he;
- struct sockaddr_in sa;
- char **ap;
- unsigned int nport;
- int cnt;
-
- get_host_and_port(&host, &port);
-
- if (flags & CONNECT_VERBOSE)
- fprintf(stderr, "Looking up %s ... ", host);
-
- he = gethostbyname(host);
- if (!he)
- die("Unable to look up %s (%s)", host, hstrerror(h_errno));
- nport = strtoul(port, &ep, 10);
- if ( ep == port || *ep ) {
- /* Not numeric */
- struct servent *se = getservbyname(port,"tcp");
- if ( !se )
- die("Unknown port %s", port);
- nport = se->s_port;
- }
-
- if (flags & CONNECT_VERBOSE)
- fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
-
- for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
- sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
- if (sockfd < 0) {
- saved_errno = errno;
- continue;
- }
-
- memset(&sa, 0, sizeof sa);
- sa.sin_family = he->h_addrtype;
- sa.sin_port = htons(nport);
- memcpy(&sa.sin_addr, *ap, he->h_length);
-
- if (connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
- saved_errno = errno;
- fprintf(stderr, "%s[%d: %s]: errno=%s\n",
- host,
- cnt,
- inet_ntoa(*(struct in_addr *)&sa.sin_addr),
- strerror(saved_errno));
- close(sockfd);
- sockfd = -1;
- continue;
- }
- if (flags & CONNECT_VERBOSE)
- fprintf(stderr, "%s ",
- inet_ntoa(*(struct in_addr *)&sa.sin_addr));
- break;
- }
-
- if (sockfd < 0)
- die("unable to connect a socket (%s)", strerror(saved_errno));
-
- if (flags & CONNECT_VERBOSE)
- fprintf(stderr, "done.\n");
-
- return sockfd;
-}
-
-#endif /* NO_IPV6 */
-
void git_tcp_connect(int fd[2], char *host, int flags)
{
int sockfd = git_tcp_connect_sock(host, flags);
--
1.7.5.3
--
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