blob: 0f32ded246d0bfdd889fdae53da0878c3f0d3d8b [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright(c) 2007 - 2008 Intel Corporation. All rights reserved.
*
* Maintained at www.Open-FCoE.org
*/
/*
* Target Discovery
*
* This block discovers all FC-4 remote ports, including FCP initiators. It
* also handles RSCN events and re-discovery if necessary.
*/
/*
* DISC LOCKING
*
* The disc mutex is can be locked when acquiring rport locks, but may not
* be held when acquiring the lport lock. Refer to fc_lport.c for more
* details.
*/
#include <linux/timer.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/rculist.h>
#include <asm/unaligned.h>
#include <scsi/fc/fc_gs.h>
#include <scsi/libfc.h>
#include "fc_libfc.h"
#define FC_DISC_RETRY_LIMIT 3 /* max retries */
#define FC_DISC_RETRY_DELAY 500UL /* (msecs) delay */
static void fc_disc_gpn_ft_req(struct fc_disc *);
static void fc_disc_gpn_ft_resp(struct fc_seq *, struct fc_frame *, void *);
static void fc_disc_done(struct fc_disc *, enum fc_disc_event);
static void fc_disc_timeout(struct work_struct *);
static int fc_disc_single(struct fc_lport *, struct fc_disc_port *);
static void fc_disc_restart(struct fc_disc *);
/**
* fc_disc_stop_rports() - Delete all the remote ports associated with the lport
* @disc: The discovery job to stop remote ports on
*/
static void fc_disc_stop_rports(struct fc_disc *disc)
{
struct fc_rport_priv *rdata;
lockdep_assert_held(&disc->disc_mutex);
list_for_each_entry(rdata, &disc->rports, peers) {
if (kref_get_unless_zero(&rdata->kref)) {
fc_rport_logoff(rdata);
kref_put(&rdata->kref, fc_rport_destroy);
}
}
}
/**
* fc_disc_recv_rscn_req() - Handle Registered State Change Notification (RSCN)
* @disc: The discovery object to which the RSCN applies
* @fp: The RSCN frame
*/
static void fc_disc_recv_rscn_req(struct fc_disc *disc, struct fc_frame *fp)
{
struct fc_lport *lport;
struct fc_els_rscn *rp;
struct fc_els_rscn_page *pp;
struct fc_seq_els_data rjt_data;
unsigned int len;
int redisc = 0;
enum fc_els_rscn_addr_fmt fmt;
LIST_HEAD(disc_ports);
struct fc_disc_port *dp, *next;
lockdep_assert_held(&disc->disc_mutex);
lport = fc_disc_lport(disc);
FC_DISC_DBG(disc, "Received an RSCN event\n");
/* make sure the frame contains an RSCN message */
rp = fc_frame_payload_get(fp, sizeof(*rp));
if (!rp)
goto reject;
/* make sure the page length is as expected (4 bytes) */
if (rp->rscn_page_len != sizeof(*pp))
goto reject;
/* get the RSCN payload length */
len = ntohs(rp->rscn_plen);
if (len < sizeof(*rp))
goto reject;
/* make sure the frame contains the expected payload */
rp = fc_frame_payload_get(fp, len);
if (!rp)
goto reject;
/* payload must be a multiple of the RSCN page size */
len -= sizeof(*rp);
if (len % sizeof(*pp))
goto reject;
for (pp = (void *)(rp + 1); len > 0; len -= sizeof(*pp), pp++) {
fmt = pp->rscn_page_flags >> ELS_RSCN_ADDR_FMT_BIT;
fmt &= ELS_RSCN_ADDR_FMT_MASK;
/*
* if we get an address format other than port
* (area, domain, fabric), then do a full discovery
*/
switch (fmt) {
case ELS_ADDR_FMT_PORT:
FC_DISC_DBG(disc, "Port address format for port "
"(%6.6x)\n", ntoh24(pp->rscn_fid));
dp = kzalloc(sizeof(*dp), GFP_KERNEL);
if (!dp) {
redisc = 1;
break;
}
dp->lp = lport;
dp->port_id = ntoh24(pp->rscn_fid);
list_add_tail(&dp->peers, &disc_ports);
break;
case ELS_ADDR_FMT_AREA:
case ELS_ADDR_FMT_DOM:
case ELS_ADDR_FMT_FAB:
default:
FC_DISC_DBG(disc, "Address format is (%d)\n", fmt);
redisc = 1;
break;
}
}
fc_seq_els_rsp_send(fp, ELS_LS_ACC, NULL);
/*
* If not doing a complete rediscovery, do GPN_ID on
* the individual ports mentioned in the list.
* If any of these get an error, do a full rediscovery.
* In any case, go through the list and free the entries.
*/
list_for_each_entry_safe(dp, next, &disc_ports, peers) {
list_del(&dp->peers);
if (!redisc)
redisc = fc_disc_single(lport, dp);
kfree(dp);
}
if (redisc) {
FC_DISC_DBG(disc, "RSCN received: rediscovering\n");
fc_disc_restart(disc);
} else {
FC_DISC_DBG(disc, "RSCN received: not rediscovering. "
"redisc %d state %d in_prog %d\n",
redisc, lport->state, disc->pending);
}
fc_frame_free(fp);
return;
reject:
FC_DISC_DBG(disc, "Received a bad RSCN frame\n");
rjt_data.reason = ELS_RJT_LOGIC;
rjt_data.explan = ELS_EXPL_NONE;
fc_seq_els_rsp_send(fp, ELS_LS_RJT, &rjt_data);
fc_frame_free(fp);
}
/**
* fc_disc_recv_req() - Handle incoming requests
* @lport: The local port receiving the request
* @fp: The request frame
*
* Locking Note: This function is called from the EM and will lock
* the disc_mutex before calling the handler for the
* request.
*/
static void fc_disc_recv_req(struct fc_lport *lport, struct fc_frame *fp)
{
u8 op;
struct fc_disc *disc = &lport->disc;
op = fc_frame_payload_op(fp);
switch (op) {
case ELS_RSCN:
mutex_lock(&disc->disc_mutex);
fc_disc_recv_rscn_req(disc, fp);
mutex_unlock(&disc->disc_mutex);
break;
default:
FC_DISC_DBG(disc, "Received an unsupported request, "
"the opcode is (%x)\n", op);
fc_frame_free(fp);
break;
}
}
/**
* fc_disc_restart() - Restart discovery
* @disc: The discovery object to be restarted
*/
static void fc_disc_restart(struct fc_disc *disc)
{
lockdep_assert_held(&disc->disc_mutex);
if (!disc->disc_callback)
return;
FC_DISC_DBG(disc, "Restarting discovery\n");
disc->requested = 1;
if (disc->pending)
return;
/*
* Advance disc_id. This is an arbitrary non-zero number that will
* match the value in the fc_rport_priv after discovery for all
* freshly-discovered remote ports. Avoid wrapping to zero.
*/
disc->disc_id = (disc->disc_id + 2) | 1;
disc->retry_count = 0;
fc_disc_gpn_ft_req(disc);
}
/**
* fc_disc_start() - Start discovery on a local port
* @lport: The local port to have discovery started on
* @disc_callback: Callback function to be called when discovery is complete
*/
static void fc_disc_start(void (*disc_callback)(struct fc_lport *,
enum fc_disc_event),
struct fc_lport *lport)
{
struct fc_disc *disc = &lport->disc;
/*
* At this point we may have a new disc job or an existing
* one. Either way, let's lock when we make changes to it
* and send the GPN_FT request.
*/
mutex_lock(&disc->disc_mutex);
disc->disc_callback = disc_callback;
fc_disc_restart(disc);
mutex_unlock(&disc->disc_mutex);
}
/**
* fc_disc_done() - Discovery has been completed
* @disc: The discovery context
* @event: The discovery completion status
*/
static void fc_disc_done(struct fc_disc *disc, enum fc_disc_event event)
{
struct fc_lport *lport = fc_disc_lport(disc);
struct fc_rport_priv *rdata;
lockdep_assert_held(&disc->disc_mutex);
FC_DISC_DBG(disc, "Discovery complete\n");
disc->pending = 0;
if (disc->requested) {
fc_disc_restart(disc);
return;
}
/*
* Go through all remote ports. If they were found in the latest
* discovery, reverify or log them in. Otherwise, log them out.
* Skip ports which were never discovered. These are the dNS port
* and ports which were created by PLOGI.
*
* We don't need to use the _rcu variant here as the rport list
* is protected by the disc mutex which is already held on entry.
*/
list_for_each_entry(rdata, &disc->rports, peers) {
if (!kref_get_unless_zero(&rdata->kref))
continue;
if (rdata->disc_id) {
if (rdata->disc_id == disc->disc_id)
fc_rport_login(rdata);
else
fc_rport_logoff(rdata);
}
kref_put(&rdata->kref, fc_rport_destroy);
}
mutex_unlock(&disc->disc_mutex);
disc->disc_callback(lport, event);
mutex_lock(&disc->disc_mutex);
}
/**
* fc_disc_error() - Handle error on dNS request
* @disc: The discovery context
* @fp: The error code encoded as a frame pointer
*/
static void fc_disc_error(struct fc_disc *disc, struct fc_frame *fp)
{
struct fc_lport *lport = fc_disc_lport(disc);
unsigned long delay = 0;
FC_DISC_DBG(disc, "Error %d, retries %d/%d\n",
PTR_ERR_OR_ZERO(fp), disc->retry_count,
FC_DISC_RETRY_LIMIT);
if (!fp || PTR_ERR(fp) == -FC_EX_TIMEOUT) {
/*
* Memory allocation failure, or the exchange timed out,
* retry after delay.
*/
if (disc->retry_count < FC_DISC_RETRY_LIMIT) {
/* go ahead and retry */
if (!fp)
delay = msecs_to_jiffies(FC_DISC_RETRY_DELAY);
else {
delay = msecs_to_jiffies(lport->e_d_tov);
/* timeout faster first time */
if (!disc->retry_count)
delay /= 4;
}
disc->retry_count++;
schedule_delayed_work(&disc->disc_work, delay);
} else
fc_disc_done(disc, DISC_EV_FAILED);
} else if (PTR_ERR(fp) == -FC_EX_CLOSED) {
/*
* if discovery fails due to lport reset, clear
* pending flag so that subsequent discovery can
* continue
*/
disc->pending = 0;
}
}
/**
* fc_disc_gpn_ft_req() - Send Get Port Names by FC-4 type (GPN_FT) request
* @disc: The discovery context
*/
static void fc_disc_gpn_ft_req(struct fc_disc *disc)
{
struct fc_frame *fp;
struct fc_lport *lport = fc_disc_lport(disc);
lockdep_assert_held(&disc->disc_mutex);
WARN_ON(!fc_lport_test_ready(lport));
disc->pending = 1;
disc->requested = 0;
disc->buf_len = 0;
disc->seq_count = 0;
fp = fc_frame_alloc(lport,
sizeof(struct fc_ct_hdr) +
sizeof(struct fc_ns_gid_ft));
if (!fp)
goto err;
if (lport->tt.elsct_send(lport, 0, fp,
FC_NS_GPN_FT,
fc_disc_gpn_ft_resp,
disc, 3 * lport->r_a_tov))
return;
err:
fc_disc_error(disc, NULL);
}
/**
* fc_disc_gpn_ft_parse() - Parse the body of the dNS GPN_FT response.
* @disc: The discovery context
* @buf: The GPN_FT response buffer
* @len: The size of response buffer
*
* Goes through the list of IDs and names resulting from a request.
*/
static int fc_disc_gpn_ft_parse(struct fc_disc *disc, void *buf, size_t len)
{
struct fc_lport *lport;
struct fc_gpn_ft_resp *np;
char *bp;
size_t plen;
size_t tlen;
int error = 0;
struct fc_rport_identifiers ids;
struct fc_rport_priv *rdata;
lport = fc_disc_lport(disc);
disc->seq_count++;
/*
* Handle partial name record left over from previous call.
*/
bp = buf;
plen = len;
np = (struct fc_gpn_ft_resp *)bp;
tlen = disc->buf_len;
disc->buf_len = 0;
if (tlen) {
WARN_ON(tlen >= sizeof(*np));
plen = sizeof(*np) - tlen;
WARN_ON(plen <= 0);
WARN_ON(plen >= sizeof(*np));
if (plen > len)
plen = len;
np = &disc->partial_buf;
memcpy((char *)np + tlen, bp, plen);
/*
* Set bp so that the loop below will advance it to the
* first valid full name element.
*/
bp -= tlen;
len += tlen;
plen += tlen;
disc->buf_len = (unsigned char) plen;
if (plen == sizeof(*np))
disc->buf_len = 0;
}
/*
* Handle full name records, including the one filled from above.
* Normally, np == bp and plen == len, but from the partial case above,
* bp, len describe the overall buffer, and np, plen describe the
* partial buffer, which if would usually be full now.
* After the first time through the loop, things return to "normal".
*/
while (plen >= sizeof(*np)) {
ids.port_id = ntoh24(np->fp_fid);
ids.port_name = ntohll(np->fp_wwpn);
if (ids.port_id != lport->port_id &&
ids.port_name != lport->wwpn) {
rdata = fc_rport_create(lport, ids.port_id);
if (rdata) {
rdata->ids.port_name = ids.port_name;
rdata->disc_id = disc->disc_id;
} else {
printk(KERN_WARNING "libfc: Failed to allocate "
"memory for the newly discovered port "
"(%6.6x)\n", ids.port_id);
error = -ENOMEM;
}
}
if (np->fp_flags & FC_NS_FID_LAST) {
fc_disc_done(disc, DISC_EV_SUCCESS);
len = 0;
break;
}
len -= sizeof(*np);
bp += sizeof(*np);
np = (struct fc_gpn_ft_resp *)bp;
plen = len;
}
/*
* Save any partial record at the end of the buffer for next time.
*/
if (error == 0 && len > 0 && len < sizeof(*np)) {
if (np != &disc->partial_buf) {
FC_DISC_DBG(disc, "Partial buffer remains "
"for discovery\n");
memcpy(&disc->partial_buf, np, len);
}
disc->buf_len = (unsigned char) len;
}
return error;
}
/**
* fc_disc_timeout() - Handler for discovery timeouts
* @work: Structure holding discovery context that needs to retry discovery
*/
static void fc_disc_timeout(struct work_struct *work)
{
struct fc_disc *disc = container_of(work,
struct fc_disc,
disc_work.work);
mutex_lock(&disc->disc_mutex);
fc_disc_gpn_ft_req(disc);
mutex_unlock(&disc->disc_mutex);
}
/**
* fc_disc_gpn_ft_resp() - Handle a response frame from Get Port Names (GPN_FT)
* @sp: The sequence that the GPN_FT response was received on
* @fp: The GPN_FT response frame
* @disc_arg: The discovery context
*
* Locking Note: This function is called without disc mutex held, and
* should do all its processing with the mutex held
*/
static void fc_disc_gpn_ft_resp(struct fc_seq *sp, struct fc_frame *fp,
void *disc_arg)
{
struct fc_disc *disc = disc_arg;
struct fc_ct_hdr *cp;
struct fc_frame_header *fh;
enum fc_disc_event event = DISC_EV_NONE;
unsigned int seq_cnt;
unsigned int len;
int error = 0;
mutex_lock(&disc->disc_mutex);
FC_DISC_DBG(disc, "Received a GPN_FT response\n");
if (IS_ERR(fp)) {
fc_disc_error(disc, fp);
mutex_unlock(&disc->disc_mutex);
return;
}
WARN_ON(!fc_frame_is_linear(fp)); /* buffer must be contiguous */
fh = fc_frame_header_get(fp);
len = fr_len(fp) - sizeof(*fh);
seq_cnt = ntohs(fh->fh_seq_cnt);
if (fr_sof(fp) == FC_SOF_I3 && seq_cnt == 0 && disc->seq_count == 0) {
cp = fc_frame_payload_get(fp, sizeof(*cp));
if (!cp) {
FC_DISC_DBG(disc, "GPN_FT response too short, len %d\n",
fr_len(fp));
event = DISC_EV_FAILED;
} else if (ntohs(cp->ct_cmd) == FC_FS_ACC) {
/* Accepted, parse the response. */
len -= sizeof(*cp);
error = fc_disc_gpn_ft_parse(disc, cp + 1, len);
} else if (ntohs(cp->ct_cmd) == FC_FS_RJT) {
FC_DISC_DBG(disc, "GPN_FT rejected reason %x exp %x "
"(check zoning)\n", cp->ct_reason,
cp->ct_explan);
event = DISC_EV_FAILED;
if (cp->ct_reason == FC_FS_RJT_UNABL &&
cp->ct_explan == FC_FS_EXP_FTNR)
event = DISC_EV_SUCCESS;
} else {
FC_DISC_DBG(disc, "GPN_FT unexpected response code "
"%x\n", ntohs(cp->ct_cmd));
event = DISC_EV_FAILED;
}
} else if (fr_sof(fp) == FC_SOF_N3 && seq_cnt == disc->seq_count) {
error = fc_disc_gpn_ft_parse(disc, fh + 1, len);
} else {
FC_DISC_DBG(disc, "GPN_FT unexpected frame - out of sequence? "
"seq_cnt %x expected %x sof %x eof %x\n",
seq_cnt, disc->seq_count, fr_sof(fp), fr_eof(fp));
event = DISC_EV_FAILED;
}
if (error)
fc_disc_error(disc, ERR_PTR(error));
else if (event != DISC_EV_NONE)
fc_disc_done(disc, event);
fc_frame_free(fp);
mutex_unlock(&disc->disc_mutex);
}
/**
* fc_disc_gpn_id_resp() - Handle a response frame from Get Port Names (GPN_ID)
* @sp: The sequence the GPN_ID is on
* @fp: The response frame
* @rdata_arg: The remote port that sent the GPN_ID response
*
* Locking Note: This function is called without disc mutex held.
*/
static void fc_disc_gpn_id_resp(struct fc_seq *sp, struct fc_frame *fp,
void *rdata_arg)
{
struct fc_rport_priv *rdata = rdata_arg;
struct fc_rport_priv *new_rdata;
struct fc_lport *lport;
struct fc_disc *disc;
struct fc_ct_hdr *cp;
struct fc_ns_gid_pn *pn;
u64 port_name;
lport = rdata->local_port;
disc = &lport->disc;
if (PTR_ERR(fp) == -FC_EX_CLOSED)
goto out;
if (IS_ERR(fp)) {
mutex_lock(&disc->disc_mutex);
fc_disc_restart(disc);
mutex_unlock(&disc->disc_mutex);
goto out;
}
cp = fc_frame_payload_get(fp, sizeof(*cp));
if (!cp)
goto redisc;
if (ntohs(cp->ct_cmd) == FC_FS_ACC) {
if (fr_len(fp) < sizeof(struct fc_frame_header) +
sizeof(*cp) + sizeof(*pn))
goto redisc;
pn = (struct fc_ns_gid_pn *)(cp + 1);
port_name = get_unaligned_be64(&pn->fn_wwpn);
mutex_lock(&rdata->rp_mutex);
if (rdata->ids.port_name == -1)
rdata->ids.port_name = port_name;
else if (rdata->ids.port_name != port_name) {
FC_DISC_DBG(disc, "GPN_ID accepted. WWPN changed. "
"Port-id %6.6x wwpn %16.16llx\n",
rdata->ids.port_id, port_name);
mutex_unlock(&rdata->rp_mutex);
fc_rport_logoff(rdata);
mutex_lock(&lport->disc.disc_mutex);
new_rdata = fc_rport_create(lport, rdata->ids.port_id);
mutex_unlock(&lport->disc.disc_mutex);
if (new_rdata) {
new_rdata->disc_id = disc->disc_id;
fc_rport_login(new_rdata);
}
goto free_fp;
}
rdata->disc_id = disc->disc_id;
mutex_unlock(&rdata->rp_mutex);
fc_rport_login(rdata);
} else if (ntohs(cp->ct_cmd) == FC_FS_RJT) {
FC_DISC_DBG(disc, "GPN_ID rejected reason %x exp %x\n",
cp->ct_reason, cp->ct_explan);
fc_rport_logoff(rdata);
} else {
FC_DISC_DBG(disc, "GPN_ID unexpected response code %x\n",
ntohs(cp->ct_cmd));
redisc:
mutex_lock(&disc->disc_mutex);
fc_disc_restart(disc);
mutex_unlock(&disc->disc_mutex);
}
free_fp:
fc_frame_free(fp);
out:
kref_put(&rdata->kref, fc_rport_destroy);
}
/**
* fc_disc_gpn_id_req() - Send Get Port Names by ID (GPN_ID) request
* @lport: The local port to initiate discovery on
* @rdata: remote port private data
*
* On failure, an error code is returned.
*/
static int fc_disc_gpn_id_req(struct fc_lport *lport,
struct fc_rport_priv *rdata)
{
struct fc_frame *fp;
lockdep_assert_held(&lport->disc.disc_mutex);
fp = fc_frame_alloc(lport, sizeof(struct fc_ct_hdr) +
sizeof(struct fc_ns_fid));
if (!fp)
return -ENOMEM;
if (!lport->tt.elsct_send(lport, rdata->ids.port_id, fp, FC_NS_GPN_ID,
fc_disc_gpn_id_resp, rdata,
3 * lport->r_a_tov))
return -ENOMEM;
kref_get(&rdata->kref);
return 0;
}
/**
* fc_disc_single() - Discover the directory information for a single target
* @lport: The local port the remote port is associated with
* @dp: The port to rediscover
*/
static int fc_disc_single(struct fc_lport *lport, struct fc_disc_port *dp)
{
struct fc_rport_priv *rdata;
lockdep_assert_held(&lport->disc.disc_mutex);
rdata = fc_rport_create(lport, dp->port_id);
if (!rdata)
return -ENOMEM;
rdata->disc_id = 0;
return fc_disc_gpn_id_req(lport, rdata);
}
/**
* fc_disc_stop() - Stop discovery for a given lport
* @lport: The local port that discovery should stop on
*/
static void fc_disc_stop(struct fc_lport *lport)
{
struct fc_disc *disc = &lport->disc;
if (disc->pending)
cancel_delayed_work_sync(&disc->disc_work);
mutex_lock(&disc->disc_mutex);
fc_disc_stop_rports(disc);
mutex_unlock(&disc->disc_mutex);
}
/**
* fc_disc_stop_final() - Stop discovery for a given lport
* @lport: The lport that discovery should stop on
*
* This function will block until discovery has been
* completely stopped and all rports have been deleted.
*/
static void fc_disc_stop_final(struct fc_lport *lport)
{
fc_disc_stop(lport);
fc_rport_flush_queue();
}
/**
* fc_disc_config() - Configure the discovery layer for a local port
* @lport: The local port that needs the discovery layer to be configured
* @priv: Private data structre for users of the discovery layer
*/
void fc_disc_config(struct fc_lport *lport, void *priv)
{
struct fc_disc *disc;
if (!lport->tt.disc_start)
lport->tt.disc_start = fc_disc_start;
if (!lport->tt.disc_stop)
lport->tt.disc_stop = fc_disc_stop;
if (!lport->tt.disc_stop_final)
lport->tt.disc_stop_final = fc_disc_stop_final;
if (!lport->tt.disc_recv_req)
lport->tt.disc_recv_req = fc_disc_recv_req;
disc = &lport->disc;
disc->priv = priv;
}
EXPORT_SYMBOL(fc_disc_config);
/**
* fc_disc_init() - Initialize the discovery layer for a local port
* @lport: The local port that needs the discovery layer to be initialized
*/
void fc_disc_init(struct fc_lport *lport)
{
struct fc_disc *disc = &lport->disc;
INIT_DELAYED_WORK(&disc->disc_work, fc_disc_timeout);
mutex_init(&disc->disc_mutex);
INIT_LIST_HEAD(&disc->rports);
}
EXPORT_SYMBOL(fc_disc_init);