slirp: Add dns6 resolution

This makes get_dns_addr address family-agnostic, thus allowing to add the
IPv6 case.

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
This commit is contained in:
Samuel Thibault 2016-03-20 15:09:09 +01:00
parent 972487b878
commit 1d17654e76
4 changed files with 69 additions and 24 deletions

View File

@ -26,6 +26,12 @@
0x00, 0x00, 0x00, 0x00,\
0x00, 0x00, 0x00, 0x02 } }
#define ZERO_ADDR { .s6_addr = \
{ 0x00, 0x00, 0x00, 0x00,\
0x00, 0x00, 0x00, 0x00,\
0x00, 0x00, 0x00, 0x00,\
0x00, 0x00, 0x00, 0x00 } }
static inline bool in6_equal(const struct in6_addr *a, const struct in6_addr *b)
{
return memcmp(a, b, sizeof(*a)) == 0;
@ -84,6 +90,9 @@ static inline bool in6_equal_mach(const struct in6_addr *a,
#define in6_solicitednode_multicast(a)\
(in6_equal_net(a, &(struct in6_addr)SOLICITED_NODE_PREFIX, 104))
#define in6_zero(a)\
(in6_equal(a, &(struct in6_addr)ZERO_ADDR))
/* Compute emulated host MAC address from its ipv6 address */
static inline void in6_compute_ethaddr(struct in6_addr ip,
uint8_t eth[ETH_ALEN])

View File

@ -7,6 +7,7 @@ struct Slirp;
typedef struct Slirp Slirp;
int get_dns_addr(struct in_addr *pdns_addr);
int get_dns6_addr(struct in6_addr *pdns6_addr);
Slirp *slirp_init(int restricted, bool in_enabled, struct in_addr vnetwork,
struct in_addr vnetmask, struct in_addr vhost,

View File

@ -46,7 +46,9 @@ static QTAILQ_HEAD(slirp_instances, Slirp) slirp_instances =
QTAILQ_HEAD_INITIALIZER(slirp_instances);
static struct in_addr dns_addr;
static struct in6_addr dns6_addr;
static u_int dns_addr_time;
static u_int dns6_addr_time;
#define TIMEOUT_FAST 2 /* milliseconds */
#define TIMEOUT_SLOW 499 /* milliseconds */
@ -100,6 +102,11 @@ int get_dns_addr(struct in_addr *pdns_addr)
return 0;
}
int get_dns6_addr(struct in6_addr *pdns_addr6)
{
return -1;
}
static void winsock_cleanup(void)
{
WSACleanup();
@ -107,36 +114,37 @@ static void winsock_cleanup(void)
#else
static struct stat dns_addr_stat;
static int get_dns_addr_cached(struct in_addr *pdns_addr)
static int get_dns_addr_cached(void *pdns_addr, void *cached_addr,
socklen_t addrlen,
struct stat *cached_stat, u_int *cached_time)
{
struct stat old_stat;
if (curtime - dns_addr_time < TIMEOUT_DEFAULT) {
*pdns_addr = dns_addr;
if (curtime - *cached_time < TIMEOUT_DEFAULT) {
memcpy(pdns_addr, cached_addr, addrlen);
return 0;
}
old_stat = dns_addr_stat;
if (stat("/etc/resolv.conf", &dns_addr_stat) != 0) {
old_stat = *cached_stat;
if (stat("/etc/resolv.conf", cached_stat) != 0) {
return -1;
}
if (dns_addr_stat.st_dev == old_stat.st_dev
&& dns_addr_stat.st_ino == old_stat.st_ino
&& dns_addr_stat.st_size == old_stat.st_size
&& dns_addr_stat.st_mtime == old_stat.st_mtime) {
*pdns_addr = dns_addr;
if (cached_stat->st_dev == old_stat.st_dev
&& cached_stat->st_ino == old_stat.st_ino
&& cached_stat->st_size == old_stat.st_size
&& cached_stat->st_mtime == old_stat.st_mtime) {
memcpy(pdns_addr, cached_addr, addrlen);
return 0;
}
return 1;
}
static int get_dns_addr_resolv_conf(struct in_addr *pdns_addr)
static int get_dns_addr_resolv_conf(int af, void *pdns_addr, void *cached_addr,
socklen_t addrlen, u_int *cached_time)
{
char buff[512];
char buff2[257];
FILE *f;
int found = 0;
struct in_addr tmp_addr;
void *tmp_addr = alloca(addrlen);
f = fopen("/etc/resolv.conf", "r");
if (!f)
@ -147,13 +155,14 @@ static int get_dns_addr_resolv_conf(struct in_addr *pdns_addr)
#endif
while (fgets(buff, 512, f) != NULL) {
if (sscanf(buff, "nameserver%*[ \t]%256s", buff2) == 1) {
if (!inet_aton(buff2, &tmp_addr))
if (!inet_pton(af, buff2, tmp_addr)) {
continue;
}
/* If it's the first one, set it to dns_addr */
if (!found) {
*pdns_addr = tmp_addr;
dns_addr = tmp_addr;
dns_addr_time = curtime;
memcpy(pdns_addr, tmp_addr, addrlen);
memcpy(cached_addr, tmp_addr, addrlen);
*cached_time = curtime;
}
#ifdef DEBUG
else
@ -166,8 +175,14 @@ static int get_dns_addr_resolv_conf(struct in_addr *pdns_addr)
break;
}
#ifdef DEBUG
else
fprintf(stderr, "%s", inet_ntoa(tmp_addr));
else {
char s[INET6_ADDRSTRLEN];
char *res = inet_ntop(af, tmp_addr, s, sizeof(s));
if (!res) {
res = "(string conversion error)";
}
fprintf(stderr, "%s", res);
}
#endif
}
}
@ -179,14 +194,34 @@ static int get_dns_addr_resolv_conf(struct in_addr *pdns_addr)
int get_dns_addr(struct in_addr *pdns_addr)
{
static struct stat dns_addr_stat;
if (dns_addr.s_addr != 0) {
int ret;
ret = get_dns_addr_cached(pdns_addr);
ret = get_dns_addr_cached(pdns_addr, &dns_addr, sizeof(dns_addr),
&dns_addr_stat, &dns_addr_time);
if (ret <= 0) {
return ret;
}
}
return get_dns_addr_resolv_conf(pdns_addr);
return get_dns_addr_resolv_conf(AF_INET, pdns_addr, &dns_addr,
sizeof(dns_addr), &dns_addr_time);
}
int get_dns6_addr(struct in6_addr *pdns6_addr)
{
static struct stat dns6_addr_stat;
if (!in6_zero(&dns6_addr)) {
int ret;
ret = get_dns_addr_cached(pdns6_addr, &dns6_addr, sizeof(dns6_addr),
&dns6_addr_stat, &dns6_addr_time);
if (ret <= 0) {
return ret;
}
}
return get_dns_addr_resolv_conf(AF_INET6, pdns6_addr, &dns6_addr,
sizeof(dns6_addr), &dns6_addr_time);
}
#endif

View File

@ -816,9 +816,9 @@ void sotranslate_out(struct socket *so, struct sockaddr_storage *addr)
if (in6_equal_net(&so->so_faddr6, &slirp->vprefix_addr6,
slirp->vprefix_len)) {
if (in6_equal(&so->so_faddr6, &slirp->vnameserver_addr6)) {
/*if (get_dns_addr(&addr) < 0) {*/ /* TODO */
if (get_dns6_addr(&sin6->sin6_addr) < 0) {
sin6->sin6_addr = in6addr_loopback;
/*}*/
}
} else {
sin6->sin6_addr = in6addr_loopback;
}