diff options
author | Steve French <stfrench@microsoft.com> | 2023-05-22 04:46:30 +0300 |
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committer | Steve French <stfrench@microsoft.com> | 2023-05-25 00:29:21 +0300 |
commit | 38c8a9a52082579090e34c033d439ed2cd1a462d (patch) | |
tree | ca6c3bf5b2b912f32735c1aa0a045cd21a47a205 /fs/smb/client/dns_resolve.c | |
parent | cb8b02fd6343228966324528adf920bfb8b8e681 (diff) | |
download | linux-38c8a9a52082579090e34c033d439ed2cd1a462d.tar.xz |
smb: move client and server files to common directory fs/smb
Move CIFS/SMB3 related client and server files (cifs.ko and ksmbd.ko
and helper modules) to new fs/smb subdirectory:
fs/cifs --> fs/smb/client
fs/ksmbd --> fs/smb/server
fs/smbfs_common --> fs/smb/common
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Diffstat (limited to 'fs/smb/client/dns_resolve.c')
-rw-r--r-- | fs/smb/client/dns_resolve.c | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/fs/smb/client/dns_resolve.c b/fs/smb/client/dns_resolve.c new file mode 100644 index 000000000000..8bf8978bc5d6 --- /dev/null +++ b/fs/smb/client/dns_resolve.c @@ -0,0 +1,88 @@ +// SPDX-License-Identifier: LGPL-2.1 +/* + * + * Copyright (c) 2007 Igor Mammedov + * Author(s): Igor Mammedov (niallain@gmail.com) + * Steve French (sfrench@us.ibm.com) + * Wang Lei (wang840925@gmail.com) + * David Howells (dhowells@redhat.com) + * + * Contains the CIFS DFS upcall routines used for hostname to + * IP address translation. + * + */ + +#include <linux/inet.h> +#include <linux/slab.h> +#include <linux/dns_resolver.h> +#include "dns_resolve.h" +#include "cifsglob.h" +#include "cifsproto.h" +#include "cifs_debug.h" + +/** + * dns_resolve_server_name_to_ip - Resolve UNC server name to ip address. + * @unc: UNC path specifying the server (with '/' as delimiter) + * @ip_addr: Where to return the IP address. + * @expiry: Where to return the expiry time for the dns record. + * + * Returns zero success, -ve on error. + */ +int +dns_resolve_server_name_to_ip(const char *unc, struct sockaddr *ip_addr, time64_t *expiry) +{ + const char *hostname, *sep; + char *ip; + int len, rc; + + if (!ip_addr || !unc) + return -EINVAL; + + len = strlen(unc); + if (len < 3) { + cifs_dbg(FYI, "%s: unc is too short: %s\n", __func__, unc); + return -EINVAL; + } + + /* Discount leading slashes for cifs */ + len -= 2; + hostname = unc + 2; + + /* Search for server name delimiter */ + sep = memchr(hostname, '/', len); + if (sep) + len = sep - hostname; + else + cifs_dbg(FYI, "%s: probably server name is whole unc: %s\n", + __func__, unc); + + /* Try to interpret hostname as an IPv4 or IPv6 address */ + rc = cifs_convert_address(ip_addr, hostname, len); + if (rc > 0) { + cifs_dbg(FYI, "%s: unc is IP, skipping dns upcall: %*.*s\n", __func__, len, len, + hostname); + return 0; + } + + /* Perform the upcall */ + rc = dns_query(current->nsproxy->net_ns, NULL, hostname, len, + NULL, &ip, expiry, false); + if (rc < 0) { + cifs_dbg(FYI, "%s: unable to resolve: %*.*s\n", + __func__, len, len, hostname); + } else { + cifs_dbg(FYI, "%s: resolved: %*.*s to %s expiry %llu\n", + __func__, len, len, hostname, ip, + expiry ? (*expiry) : 0); + + rc = cifs_convert_address(ip_addr, ip, strlen(ip)); + kfree(ip); + + if (!rc) { + cifs_dbg(FYI, "%s: unable to determine ip address\n", __func__); + rc = -EHOSTUNREACH; + } else + rc = 0; + } + return rc; +} |