fabrics: allow traddr to be host name for ip based transports

Some users would like to use well known hostnames instead of remembering
ip addresses. So, allow users to set traddr to be a host name and we will
attempt to resolve against a DNS.

This applies for IP based transports only (e.g. tcp, rdma) while fc and
loop will ignore this distinction.

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>

diff --git a/fabrics.c b/fabrics.c
index 372bc1dd3ce83616ad2cfc7905034a8c9e1a1237..e73d6ad18a2e1f373a10437c8e6b9886983af651 100644 (file)
--- a/fabrics.c
+++ b/fabrics.c
@@ -33,6 +33,10 @@
 #include <sys/stat.h>
 #include <stddef.h>
 
+#include <sys/types.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+
 #include "util/parser.h"
 #include "nvme-ioctl.h"
 #include "nvme-status.h"
@@ -857,6 +861,63 @@ static int build_options(char *argstr, int max_len, bool discover)
        return 0;
 }
 
+static bool traddr_is_hostname(struct config *cfg)
+{
+       char addrstr[NVMF_TRADDR_SIZE];
+
+       if (!cfg->traddr)
+               return false;
+       if (strcmp(cfg->transport, "tcp") && strcmp(cfg->transport, "rdma"))
+               return false;
+       if (inet_pton(AF_INET, cfg->traddr, addrstr) > 0 ||
+           inet_pton(AF_INET6, cfg->traddr, addrstr) > 0)
+               return false;
+       return true;
+}
+
+static int hostname2traddr(struct config *cfg)
+{
+       struct addrinfo *host_info, hints = {.ai_family = AF_UNSPEC};
+       char addrstr[NVMF_TRADDR_SIZE];
+       const char *p;
+       int ret;
+
+       ret = getaddrinfo(cfg->traddr, NULL, &hints, &host_info);
+       if (ret) {
+               fprintf(stderr, "failed to resolve host %s info\n", cfg->traddr);
+               return ret;
+       }
+
+       switch (host_info->ai_family) {
+       case AF_INET:
+               p = inet_ntop(host_info->ai_family,
+                       &(((struct sockaddr_in *)host_info->ai_addr)->sin_addr),
+                       addrstr, NVMF_TRADDR_SIZE);
+               break;
+       case AF_INET6:
+               p = inet_ntop(host_info->ai_family,
+                       &(((struct sockaddr_in6 *)host_info->ai_addr)->sin6_addr),
+                       addrstr, NVMF_TRADDR_SIZE);
+               break;
+       default:
+               fprintf(stderr, "unrecognized address family (%d) %s\n",
+                       host_info->ai_family, cfg->traddr);
+               ret = -EINVAL;
+               goto free_addrinfo;
+       }
+
+       if (!p) {
+               fprintf(stderr, "failed to get traddr for %s\n", cfg->traddr);
+               ret = -errno;
+               goto free_addrinfo;
+       }
+       cfg->traddr = strdup(addrstr);
+
+free_addrinfo:
+       freeaddrinfo(host_info);
+       return ret;
+}
+
 static int connect_ctrl(struct nvmf_disc_rsp_page_entry *e)
 {
        char argstr[BUF_SIZE], *p;
@@ -1230,6 +1291,12 @@ static int discover_from_conf_file(const char *desc, char *argstr,
                if (cfg.persistent && !cfg.keep_alive_tmo)
                        cfg.keep_alive_tmo = NVMF_DEF_DISC_TMO;
 
+               if (traddr_is_hostname(&cfg)) {
+                       ret = hostname2traddr(&cfg);
+                       if (ret)
+                               goto out;
+               }
+
                err = build_options(argstr, BUF_SIZE, true);
                if (err) {
                        ret = err;
@@ -1294,6 +1361,13 @@ int fabrics_discover(const char *desc, int argc, char **argv, bool connect)
        } else {
                if (cfg.persistent && !cfg.keep_alive_tmo)
                        cfg.keep_alive_tmo = NVMF_DEF_DISC_TMO;
+
+               if (traddr_is_hostname(&cfg)) {
+                       ret = hostname2traddr(&cfg);
+                       if (ret)
+                               goto out;
+               }
+
                ret = build_options(argstr, BUF_SIZE, true);
                if (ret)
                        goto out;
@@ -1338,6 +1412,12 @@ int fabrics_connect(const char *desc, int argc, char **argv)
        if (ret)
                goto out;
 
+       if (traddr_is_hostname(&cfg)) {
+               ret = hostname2traddr(&cfg);
+               if (ret)
+                       goto out;
+       }
+
        ret = build_options(argstr, BUF_SIZE, false);
        if (ret)
                goto out;