2016-11-08 8:33 GMT-08:00 Aurelien Aptel <aaptel@xxxxxxxx>:
> Few issues with the current situation
>
> * the get_dfs_refer op is meant to be used from cifs thus the prototype
> of the operation is not adapted for smb2:
>
> - it passes a session as opposed to a tcon like other smb2 operations,
> which means we have to find the corresponding tcon ourselves. see
> new function find_session_tcon() which currently assumes the first one
> is the right one.
I think it is ok since it matches the spec which suggests to find any
ses and tcon.
>
> - it doesn't pass a cifs_sb so we cannot use the usual utf16
> conversion function used in the rest of smb2 code
I suggest to pass cifs_sb to get_dfs_path() (instead of
cifs_remap(cifs_sb)) and then modify a get_dfs_refer() callback to
take cifs_sb as well. This let us use cifs_convert_path_to_utf16().
>
> * the DFS request has to be made on the IPC tcon and i'm not really sure
> how to get to it since it doesnt seem to be part of the session tcon
> list.
Should we probably add an extra param to SMB2_ioctl called ipc_tid? In
case when tcon passed to this function is NULL ipc_tid will be used in
a similar manner how it is done now for CIFS. Otherwise (if tcon is
not NULL) tcon is used as it is now.
>
> * the function that extracts the data from the responce is almost
> entirely copied and adapted from the smb1 code. ideally they should be
> merged.
>
> Signed-off-by: Aurelien Aptel <aaptel@xxxxxxxx>
> ---
> fs/cifs/smb2ops.c | 206 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 206 insertions(+)
>
> diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
> index 5d456eb..677579b 100644
> --- a/fs/cifs/smb2ops.c
> +++ b/fs/cifs/smb2ops.c
> @@ -1093,6 +1093,212 @@ smb2_new_lease_key(struct cifs_fid *fid)
> generate_random_uuid(fid->lease_key);
> }
>
> +/*
> + * XXX: Return the tcon currently used in the session
> + */
> +static struct cifs_tcon *
> +find_session_tcon (struct cifs_ses *ses)
> +{
> + struct cifs_tcon *tcon = NULL, *it;
> + struct list_head *tmp;
> + int i = 0;
> +
> + spin_lock(&cifs_tcp_ses_lock);
> + list_for_each(tmp, &ses->tcon_list) {
> + it = list_entry(tmp, struct cifs_tcon, tcon_list);
> + cifs_dbg(FYI, "XXX: [%d] tcon %p\n", i, it);
> +
> + /* XXX: Assumes the first one is always the right one. */
> + if (i == 0) {
> + tcon = it;
> + }
> + i++;
> + }
> + spin_unlock(&cifs_tcp_ses_lock);
> +
> + if (!tcon)
> + cifs_dbg(FYI, "XXX: cannot find our tcon\n");
> + return tcon;
> +}
> +
> +/*
> + * XXX: Copied and adapted from parse_DFS_referrals in cifssmb.c
> + * TODO: extract logic in a SMB agnostic way
> + */
> +static int
> +smb2_parse_dfs_referrers_rsp(struct fsctl_get_dfs_referral_rsp *rsp, u32 rsp_size,
> + unsigned int *num_of_nodes,
> + struct dfs_info3_param **target_nodes,
> + const struct nls_table *nls_codepage, int remap,
> + const char *searchName)
> +{
> + int i, rc = 0;
> + char *data_end;
> + bool is_unicode = true;
> + struct dfs_referral_level_3 *ref;
> +
> + *num_of_nodes = le16_to_cpu(rsp->NumberOfReferrals);
> +
> + if (*num_of_nodes < 1) {
> + cifs_dbg(VFS, "num_referrals: must be at least > 0, but we get num_referrals = %d\n",
> + *num_of_nodes);
> + rc = -EINVAL;
> + goto parse_DFS_referrals_exit;
> + }
> +
> + ref = (struct dfs_referral_level_3 *) &rsp->buffer[0];
> + if (ref->VersionNumber != cpu_to_le16(3)) {
> + cifs_dbg(VFS, "Referrals of V%d version are not supported, should be V3\n",
> + le16_to_cpu(ref->VersionNumber));
> + rc = -EINVAL;
> + goto parse_DFS_referrals_exit;
> + }
> +
> + /* get the upper boundary of the resp buffer */
> + data_end = (char *)(&(rsp->PathConsumed)) + rsp_size;
> +
> + cifs_dbg(FYI, "num_referrals: %d dfs flags: 0x%x ...\n",
> + *num_of_nodes, le32_to_cpu(rsp->ReferralHeaderFlags));
> +
> + *target_nodes = kcalloc(*num_of_nodes, sizeof(struct dfs_info3_param),
> + GFP_KERNEL);
> + if (*target_nodes == NULL) {
> + rc = -ENOMEM;
> + goto parse_DFS_referrals_exit;
> + }
> +
> + /* collect necessary data from referrals */
> + for (i = 0; i < *num_of_nodes; i++) {
> + char *temp;
> + int max_len;
> + __le16 *tmp;
> + struct dfs_info3_param *node = (*target_nodes)+i;
> +
> + node->flags = le32_to_cpu(rsp->ReferralHeaderFlags);
> + tmp = kmalloc(strlen(searchName)*2 + 2,
> + GFP_KERNEL);
> + if (tmp == NULL) {
> + rc = -ENOMEM;
> + goto parse_DFS_referrals_exit;
> + }
> + cifsConvertToUTF16((__le16 *) tmp, searchName,
> + PATH_MAX, nls_codepage, remap);
> + node->path_consumed = cifs_utf16_bytes(tmp,
> + le16_to_cpu(rsp->PathConsumed),
> + nls_codepage);
> + kfree(tmp);
> +
> + node->server_type = le16_to_cpu(ref->ServerType);
> + node->ref_flag = le16_to_cpu(ref->ReferralEntryFlags);
> +
> + /* copy DfsPath */
> + temp = (char *)ref + le16_to_cpu(ref->DfsPathOffset);
> + max_len = data_end - temp;
> + node->path_name = cifs_strndup_from_utf16(temp, max_len,
> + true /* is_unicode */, nls_codepage);
> + if (!node->path_name) {
> + rc = -ENOMEM;
> + goto parse_DFS_referrals_exit;
> + }
> +
> + /* copy link target UNC */
> + temp = (char *)ref + le16_to_cpu(ref->NetworkAddressOffset);
> + max_len = data_end - temp;
> + node->node_name = cifs_strndup_from_utf16(temp, max_len,
> + is_unicode, nls_codepage);
> + if (!node->node_name) {
> + rc = -ENOMEM;
> + goto parse_DFS_referrals_exit;
> + }
> +
> + ref++;
> + }
> +
> +parse_DFS_referrals_exit:
> + if (rc) {
> + free_dfs_info_array(*target_nodes, *num_of_nodes);
> + *target_nodes = NULL;
> + *num_of_nodes = 0;
> + }
> + return rc;
> +}
> +
> +
> +static int
> +smb2_get_dfs_refer(const unsigned int xid, struct cifs_ses *ses,
> + const char *search_name, struct dfs_info3_param **target_nodes,
> + unsigned int *num_of_nodes,
> + const struct nls_table *nls_codepage, int remap)
> +{
> + int rc = -ENOSYS;
> + __le16 *utf16_path = NULL;
> + int utf16_path_len = 0;
> + struct cifs_tcon *tcon;
> + struct fsctl_get_dfs_referral_req *dfs_req = NULL;
> + struct fsctl_get_dfs_referral_rsp *dfs_rsp = NULL;
> + u32 dfs_req_size = 0, dfs_rsp_size = 0;
> +
> + cifs_dbg(FYI, "XXX: In smb2_get_dfs_refer the path <%s> %d\n", search_name, (int)strlen(search_name));
> +
> + /*
> + * XXX: Find this session tcon. We shouldnt have to do this
> + * proper solution would be to update get_dfs_refer op
> + * prototype to pass it somehow.
> + */
> + tcon = find_session_tcon(ses);
> + if (!tcon)
> + goto out;
> +
> + /*
> + * XXX: Should we use use cifs_convert_path_to_utf16(full_path, cifs_sb) instead?
> + * it needs cifs_sb superblock pointer which we don't have...
> + */
> +
> + utf16_path_len = strlen(search_name) * 2;
> + utf16_path = kzalloc(utf16_path_len + 2, GFP_KERNEL);
> + if (!utf16_path) {
> + rc = -ENOMEM;
> + goto out;
> + }
> +
> + cifsConvertToUTF16(utf16_path,
> + search_name, PATH_MAX, nls_codepage,
> + remap);
> +
> + dfs_req_size = sizeof(*dfs_req) + utf16_path_len + 2;
> + dfs_req = kzalloc(dfs_req_size, GFP_KERNEL);
> + if (!dfs_req) {
> + rc = -ENOMEM;
> + goto out;
> + }
> +
> + /* Highest DFS referral version understood (actually the only supported one) */
> + dfs_req->MaxReferralLevel = cpu_to_le16(DFS_VERSION);
> + /* Path to resolve in an UTF-16 null-terminated string */
> + memcpy(dfs_req->RequestFileName, utf16_path, utf16_path_len);
> +
> + do {
> + rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
> + FSCTL_DFS_GET_REFERRALS, true /* is_fsctl */,
> + (char *)dfs_req, dfs_req_size,
> + (char **)&dfs_rsp, &dfs_rsp_size);
> + if (rc) {
> + cifs_dbg(FYI, "SMB2_ioctl error in smb2_get_dfs_refer rc=%d\n", rc);
> + goto out;
> + }
> +
> + rc = smb2_parse_dfs_referrers_rsp(dfs_rsp, dfs_rsp_size,
> + num_of_nodes, target_nodes,
> + nls_codepage, remap, search_name);
> + kfree(dfs_rsp);
> + } while (rc == -EAGAIN);
> +
> + out:
> + kfree(utf16_path);
> + kfree(dfs_req);
> + return rc;
> +}
> +
> #define SMB2_SYMLINK_STRUCT_SIZE \
> (sizeof(struct smb2_err_rsp) - 1 + sizeof(struct smb2_symlink_err_rsp))
>
> --
> 2.1.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-cifs" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
Best regards,
Pavel Shilovsky
--
To unsubscribe from this list: send the line "unsubscribe linux-cifs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
