path: root/fs/cifs/sess.c

// SPDX-License-Identifier: LGPL-2.1
/*
 *
 *   SMB/CIFS session setup handling routines
 *
 *   Copyright (c) International Business Machines  Corp., 2006, 2009
 *   Author(s): Steve French (sfrench@us.ibm.com)
 *
 */

#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_unicode.h"
#include "cifs_debug.h"
#include "ntlmssp.h"
#include "nterr.h"
#include <linux/utsname.h>
#include <linux/slab.h>
#include "cifs_spnego.h"
#include "smb2proto.h"
#include "fs_context.h"

static int
cifs_ses_add_channel(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses,
		     struct cifs_server_iface *iface);

bool
is_server_using_iface(struct TCP_Server_Info *server,
		      struct cifs_server_iface *iface)
{
	struct sockaddr_in *i4 = (struct sockaddr_in *)&iface->sockaddr;
	struct sockaddr_in6 *i6 = (struct sockaddr_in6 *)&iface->sockaddr;
	struct sockaddr_in *s4 = (struct sockaddr_in *)&server->dstaddr;
	struct sockaddr_in6 *s6 = (struct sockaddr_in6 *)&server->dstaddr;

	if (server->dstaddr.ss_family != iface->sockaddr.ss_family)
		return false;
	if (server->dstaddr.ss_family == AF_INET) {
		if (s4->sin_addr.s_addr != i4->sin_addr.s_addr)
			return false;
	} else if (server->dstaddr.ss_family == AF_INET6) {
		if (memcmp(&s6->sin6_addr, &i6->sin6_addr,
			   sizeof(i6->sin6_addr)) != 0)
			return false;
	} else {
		/* unknown family.. */
		return false;
	}
	return true;
}

bool is_ses_using_iface(struct cifs_ses *ses, struct cifs_server_iface *iface)
{
	int i;

	spin_lock(&ses->chan_lock);
	for (i = 0; i < ses->chan_count; i++) {
		if (is_server_using_iface(ses->chans[i].server, iface)) {
			spin_unlock(&ses->chan_lock);
			return true;
		}
	}
	spin_unlock(&ses->chan_lock);
	return false;
}

/* returns number of channels added */
int cifs_try_adding_channels(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses)
{
	int old_chan_count, new_chan_count;
	int left;
	int i = 0;
	int rc = 0;
	int tries = 0;
	struct cifs_server_iface *ifaces = NULL;
	size_t iface_count;

	if (ses->server->dialect < SMB30_PROT_ID) {
		cifs_dbg(VFS, "multichannel is not supported on this protocol version, use 3.0 or above\n");
		return 0;
	}

	spin_lock(&ses->chan_lock);

	new_chan_count = old_chan_count = ses->chan_count;
	left = ses->chan_max - ses->chan_count;

	if (left <= 0) {
		cifs_dbg(FYI,
			 "ses already at max_channels (%zu), nothing to open\n",
			 ses->chan_max);
		spin_unlock(&ses->chan_lock);
		return 0;
	}

	if (!(ses->server->capabilities & SMB2_GLOBAL_CAP_MULTI_CHANNEL)) {
		ses->chan_max = 1;
		spin_unlock(&ses->chan_lock);
		cifs_dbg(VFS, "server %s does not support multichannel\n", ses->server->hostname);
		return 0;
	}
	spin_unlock(&ses->chan_lock);

	/*
	 * Make a copy of the iface list at the time and use that
	 * instead so as to not hold the iface spinlock for opening
	 * channels
	 */
	spin_lock(&ses->iface_lock);
	iface_count = ses->iface_count;
	if (iface_count <= 0) {
		spin_unlock(&ses->iface_lock);
		cifs_dbg(VFS, "no iface list available to open channels\n");
		return 0;
	}
	ifaces = kmemdup(ses->iface_list, iface_count*sizeof(*ifaces),
			 GFP_ATOMIC);
	if (!ifaces) {
		spin_unlock(&ses->iface_lock);
		return 0;
	}
	spin_unlock(&ses->iface_lock);

	/*
	 * Keep connecting to same, fastest, iface for all channels as
	 * long as its RSS. Try next fastest one if not RSS or channel
	 * creation fails.
	 */
	while (left > 0) {
		struct cifs_server_iface *iface;

		tries++;
		if (tries > 3*ses->chan_max) {
			cifs_dbg(FYI, "too many channel open attempts (%d channels left to open)\n",
				 left);
			break;
		}

		iface = &ifaces[i];
		if (is_ses_using_iface(ses, iface) && !iface->rss_capable) {
			i = (i+1) % iface_count;
			continue;
		}

		rc = cifs_ses_add_channel(cifs_sb, ses, iface);
		if (rc) {
			cifs_dbg(FYI, "failed to open extra channel on iface#%d rc=%d\n",
				 i, rc);
			i = (i+1) % iface_count;
			continue;
		}

		cifs_dbg(FYI, "successfully opened new channel on iface#%d\n",
			 i);
		left--;
		new_chan_count++;
	}

	kfree(ifaces);
	return new_chan_count - old_chan_count;
}

/*
 * If server is a channel of ses, return the corresponding enclosing
 * cifs_chan otherwise return NULL.
 */
struct cifs_chan *
cifs_ses_find_chan(struct cifs_ses *ses, struct TCP_Server_Info *server)
{
	int i;

	spin_lock(&ses->chan_lock);
	for (i = 0; i < ses->chan_count; i++) {
		if (ses->chans[i].server == server) {
			spin_unlock(&ses->chan_lock);
			return &ses->chans[i];
		}
	}
	spin_unlock(&ses->chan_lock);
	return NULL;
}

static int
cifs_ses_add_channel(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses,
		     struct cifs_server_iface *iface)
{
	struct TCP_Server_Info *chan_server;
	struct cifs_chan *chan;
	struct smb3_fs_context ctx = {NULL};
	static const char unc_fmt[] = "\\%s\\foo";
	char unc[sizeof(unc_fmt)+SERVER_NAME_LEN_WITH_NULL] = {0};
	struct sockaddr_in *ipv4 = (struct sockaddr_in *)&iface->sockaddr;
	struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)&iface->sockaddr;
	int rc;
	unsigned int xid = get_xid();

	if (iface->sockaddr.ss_family == AF_INET)
		cifs_dbg(FYI, "adding channel to ses %p (speed:%zu bps rdma:%s ip:%pI4)\n",
			 ses, iface->speed, iface->rdma_capable ? "yes" : "no",
			 &ipv4->sin_addr);
	else
		cifs_dbg(FYI, "adding channel to ses %p (speed:%zu bps rdma:%s ip:%pI6)\n",
			 ses, iface->speed, iface->rdma_capable ? "yes" : "no",
			 &ipv6->sin6_addr);

	/*
	 * Setup a ctx with mostly the same info as the existing
	 * session and overwrite it with the requested iface data.
	 *
	 * We need to setup at least the fields used for negprot and
	 * sesssetup.
	 *
	 * We only need the ctx here, so we can reu