diff options
| -rw-r--r-- | net/ceph/Kconfig | 14 | ||||
| -rw-r--r-- | net/ceph/messenger.c | 114 |
2 files changed, 116 insertions, 12 deletions
diff --git a/net/ceph/Kconfig b/net/ceph/Kconfig index be683f2d401f..cc04dd667a10 100644 --- a/net/ceph/Kconfig +++ b/net/ceph/Kconfig @@ -27,3 +27,17 @@ config CEPH_LIB_PRETTYDEBUG If unsure, say N. +config CEPH_LIB_USE_DNS_RESOLVER + bool "Use in-kernel support for DNS lookup" + depends on CEPH_LIB + select DNS_RESOLVER + default n + help + If you say Y here, hostnames (e.g. monitor addresses) will + be resolved using the CONFIG_DNS_RESOLVER facility. + + For information on how to use CONFIG_DNS_RESOLVER consult + Documentation/networking/dns_resolver.txt + + If unsure, say N. + diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c index f56aca302617..f466930e26fa 100644 --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -11,6 +11,7 @@ #include <linux/string.h> #include <linux/bio.h> #include <linux/blkdev.h> +#include <linux/dns_resolver.h> #include <net/tcp.h> #include <linux/ceph/libceph.h> @@ -1078,6 +1079,101 @@ static void addr_set_port(struct sockaddr_storage *ss, int p) } /* + * Unlike other *_pton function semantics, zero indicates success. + */ +static int ceph_pton(const char *str, size_t len, struct sockaddr_storage *ss, + char delim, const char **ipend) +{ + struct sockaddr_in *in4 = (void *)ss; + struct sockaddr_in6 *in6 = (void *)ss; + + memset(ss, 0, sizeof(*ss)); + + if (in4_pton(str, len, (u8 *)&in4->sin_addr.s_addr, delim, ipend)) { + ss->ss_family = AF_INET; + return 0; + } + + if (in6_pton(str, len, (u8 *)&in6->sin6_addr.s6_addr, delim, ipend)) { + ss->ss_family = AF_INET6; + return 0; + } + + return -EINVAL; +} + +/* + * Extract hostname string and resolve using kernel DNS facility. + */ +#ifdef CONFIG_CEPH_LIB_USE_DNS_RESOLVER +static int ceph_dns_resolve_name(const char *name, size_t namelen, + struct sockaddr_storage *ss, char delim, const char **ipend) +{ + const char *end, *delim_p; + char *colon_p, *ip_addr = NULL; + int ip_len, ret; + + /* + * The end of the hostname occurs immediately preceding the delimiter or + * the port marker (':') where the delimiter takes precedence. + */ + delim_p = memchr(name, delim, namelen); + colon_p = memchr(name, ':', namelen); + + if (delim_p && colon_p) + end = delim_p < colon_p ? delim_p : colon_p; + else if (!delim_p && colon_p) + end = colon_p; + else { + end = delim_p; + if (!end) /* case: hostname:/ */ + end = name + namelen; + } + + if (end <= name) + return -EINVAL; + + /* do dns_resolve upcall */ + ip_len = dns_query(NULL, name, end - name, NULL, &ip_addr, NULL); + if (ip_len > 0) + ret = ceph_pton(ip_addr, ip_len, ss, -1, NULL); + else + ret = -ESRCH; + + kfree(ip_addr); + + *ipend = end; + + pr_info("resolve '%.*s' (ret=%d): %s\n", (int)(end - name), name, + ret, ret ? "failed" : ceph_pr_addr(ss)); + + return ret; +} +#else +static inline int ceph_dns_resolve_name(const char *name, size_t namelen, + struct sockaddr_storage *ss, char delim, const char **ipend) +{ + return -EINVAL; +} +#endif + +/* + * Parse a server name (IP or hostname). If a valid IP address is not found + * then try to extract a hostname to resolve using userspace DNS upcall. + */ +static int ceph_parse_server_name(const char *name, size_t namelen, + struct sockaddr_storage *ss, char delim, const char **ipend) +{ + int ret; + + ret = ceph_pton(name, namelen, ss, delim, ipend); + if (ret) + ret = ceph_dns_resolve_name(name, namelen, ss, delim, ipend); + + return ret; +} + +/* * Parse an ip[:port] list into an addr array. Use the default * monitor port if a port isn't specified. */ @@ -1085,15 +1181,13 @@ int ceph_parse_ips(const char *c, const char *end, struct ceph_entity_addr *addr, int max_count, int *count) { - int i; + int i, ret = -EINVAL; const char *p = c; dout("parse_ips on '%.*s'\n", (int)(end-c), c); for (i = 0; i < max_count; i++) { const char *ipend; struct sockaddr_storage *ss = &addr[i].in_addr; - struct sockaddr_in *in4 = (void *)ss; - struct sockaddr_in6 *in6 = (void *)ss; int port; char delim = ','; @@ -1102,15 +1196,11 @@ int ceph_parse_ips(const char *c, const char *end, p++; } - memset(ss, 0, sizeof(*ss)); - if (in4_pton(p, end - p, (u8 *)&in4->sin_addr.s_addr, - delim, &ipend)) - ss->ss_family = AF_INET; - else if (in6_pton(p, end - p, (u8 *)&in6->sin6_addr.s6_addr, - delim, &ipend)) - ss->ss_family = AF_INET6; - else + ret = ceph_parse_server_name(p, end - p, ss, delim, &ipend); + if (ret) goto bad; + ret = -EINVAL; + p = ipend; if (delim == ']') { @@ -1155,7 +1245,7 @@ int ceph_parse_ips(const char *c, const char *end, bad: pr_err("parse_ips bad ip '%.*s'\n", (int)(end - c), c); - return -EINVAL; + return ret; } EXPORT_SYMBOL(ceph_parse_ips); |