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svcsock.c
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svcsock.c
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// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/net/sunrpc/svcsock.c
*
* These are the RPC server socket internals.
*
* The server scheduling algorithm does not always distribute the load
* evenly when servicing a single client. May need to modify the
* svc_xprt_enqueue procedure...
*
* TCP support is largely untested and may be a little slow. The problem
* is that we currently do two separate recvfrom's, one for the 4-byte
* record length, and the second for the actual record. This could possibly
* be improved by always reading a minimum size of around 100 bytes and
* tucking any superfluous bytes away in a temporary store. Still, that
* leaves write requests out in the rain. An alternative may be to peek at
* the first skb in the queue, and if it matches the next TCP sequence
* number, to extract the record marker. Yuck.
*
* Copyright (C) 1995, 1996 Olaf Kirch <[email protected]>
*/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fcntl.h>
#include <linux/net.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/udp.h>
#include <linux/tcp.h>
#include <linux/unistd.h>
#include <linux/slab.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/file.h>
#include <linux/freezer.h>
#include <net/sock.h>
#include <net/checksum.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <net/udp.h>
#include <net/tcp.h>
#include <net/tcp_states.h>
#include <linux/uaccess.h>
#include <linux/highmem.h>
#include <asm/ioctls.h>
#include <linux/sunrpc/types.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/msg_prot.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/sunrpc/stats.h>
#include <linux/sunrpc/xprt.h>
#include <trace/events/sunrpc.h>
#include "socklib.h"
#include "sunrpc.h"
#define RPCDBG_FACILITY RPCDBG_SVCXPRT
static struct svc_sock *svc_setup_socket(struct svc_serv *, struct socket *,
int flags);
static int svc_udp_recvfrom(struct svc_rqst *);
static int svc_udp_sendto(struct svc_rqst *);
static void svc_sock_detach(struct svc_xprt *);
static void svc_tcp_sock_detach(struct svc_xprt *);
static void svc_sock_free(struct svc_xprt *);
static struct svc_xprt *svc_create_socket(struct svc_serv *, int,
struct net *, struct sockaddr *,
int, int);
#ifdef CONFIG_DEBUG_LOCK_ALLOC
static struct lock_class_key svc_key[2];
static struct lock_class_key svc_slock_key[2];
static void svc_reclassify_socket(struct socket *sock)
{
struct sock *sk = sock->sk;
if (WARN_ON_ONCE(!sock_allow_reclassification(sk)))
return;
switch (sk->sk_family) {
case AF_INET:
sock_lock_init_class_and_name(sk, "slock-AF_INET-NFSD",
&svc_slock_key[0],
"sk_xprt.xpt_lock-AF_INET-NFSD",
&svc_key[0]);
break;
case AF_INET6:
sock_lock_init_class_and_name(sk, "slock-AF_INET6-NFSD",
&svc_slock_key[1],
"sk_xprt.xpt_lock-AF_INET6-NFSD",
&svc_key[1]);
break;
default:
BUG();
}
}
#else
static void svc_reclassify_socket(struct socket *sock)
{
}
#endif
/**
* svc_tcp_release_rqst - Release transport-related resources
* @rqstp: request structure with resources to be released
*
*/
static void svc_tcp_release_rqst(struct svc_rqst *rqstp)
{
struct sk_buff *skb = rqstp->rq_xprt_ctxt;
if (skb) {
struct svc_sock *svsk =
container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
rqstp->rq_xprt_ctxt = NULL;
skb_free_datagram_locked(svsk->sk_sk, skb);
}
}
/**
* svc_udp_release_rqst - Release transport-related resources
* @rqstp: request structure with resources to be released
*
*/
static void svc_udp_release_rqst(struct svc_rqst *rqstp)
{
struct sk_buff *skb = rqstp->rq_xprt_ctxt;
if (skb) {
rqstp->rq_xprt_ctxt = NULL;
consume_skb(skb);
}
}
union svc_pktinfo_u {
struct in_pktinfo pkti;
struct in6_pktinfo pkti6;
};
#define SVC_PKTINFO_SPACE \
CMSG_SPACE(sizeof(union svc_pktinfo_u))
static void svc_set_cmsg_data(struct svc_rqst *rqstp, struct cmsghdr *cmh)
{
struct svc_sock *svsk =
container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
switch (svsk->sk_sk->sk_family) {
case AF_INET: {
struct in_pktinfo *pki = CMSG_DATA(cmh);
cmh->cmsg_level = SOL_IP;
cmh->cmsg_type = IP_PKTINFO;
pki->ipi_ifindex = 0;
pki->ipi_spec_dst.s_addr =
svc_daddr_in(rqstp)->sin_addr.s_addr;
cmh->cmsg_len = CMSG_LEN(sizeof(*pki));
}
break;
case AF_INET6: {
struct in6_pktinfo *pki = CMSG_DATA(cmh);
struct sockaddr_in6 *daddr = svc_daddr_in6(rqstp);
cmh->cmsg_level = SOL_IPV6;
cmh->cmsg_type = IPV6_PKTINFO;
pki->ipi6_ifindex = daddr->sin6_scope_id;
pki->ipi6_addr = daddr->sin6_addr;
cmh->cmsg_len = CMSG_LEN(sizeof(*pki));
}
break;
}
}
static int svc_sock_result_payload(struct svc_rqst *rqstp, unsigned int offset,
unsigned int length)
{
return 0;
}
/*
* Report socket names for nfsdfs
*/
static int svc_one_sock_name(struct svc_sock *svsk, char *buf, int remaining)
{
const struct sock *sk = svsk->sk_sk;
const char *proto_name = sk->sk_protocol == IPPROTO_UDP ?
"udp" : "tcp";
int len;
switch (sk->sk_family) {
case PF_INET:
len = snprintf(buf, remaining, "ipv4 %s %pI4 %d\n",
proto_name,
&inet_sk(sk)->inet_rcv_saddr,
inet_sk(sk)->inet_num);
break;
#if IS_ENABLED(CONFIG_IPV6)
case PF_INET6:
len = snprintf(buf, remaining, "ipv6 %s %pI6 %d\n",
proto_name,
&sk->sk_v6_rcv_saddr,
inet_sk(sk)->inet_num);
break;
#endif
default:
len = snprintf(buf, remaining, "*unknown-%d*\n",
sk->sk_family);
}
if (len >= remaining) {
*buf = '\0';
return -ENAMETOOLONG;
}
return len;
}
#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
static void svc_flush_bvec(const struct bio_vec *bvec, size_t size, size_t seek)
{
struct bvec_iter bi = {
.bi_size = size + seek,
};
struct bio_vec bv;
bvec_iter_advance(bvec, &bi, seek & PAGE_MASK);
for_each_bvec(bv, bvec, bi, bi)
flush_dcache_page(bv.bv_page);
}
#else
static inline void svc_flush_bvec(const struct bio_vec *bvec, size_t size,
size_t seek)
{
}
#endif
/*
* Read from @rqstp's transport socket. The incoming message fills whole
* pages in @rqstp's rq_pages array until the last page of the message
* has been received into a partial page.
*/
static ssize_t svc_tcp_read_msg(struct svc_rqst *rqstp, size_t buflen,
size_t seek)
{
struct svc_sock *svsk =
container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
struct bio_vec *bvec = rqstp->rq_bvec;
struct msghdr msg = { NULL };
unsigned int i;
ssize_t len;
size_t t;
rqstp->rq_xprt_hlen = 0;
clear_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
for (i = 0, t = 0; t < buflen; i++, t += PAGE_SIZE) {
bvec[i].bv_page = rqstp->rq_pages[i];
bvec[i].bv_len = PAGE_SIZE;
bvec[i].bv_offset = 0;
}
rqstp->rq_respages = &rqstp->rq_pages[i];
rqstp->rq_next_page = rqstp->rq_respages + 1;
iov_iter_bvec(&msg.msg_iter, READ, bvec, i, buflen);
if (seek) {
iov_iter_advance(&msg.msg_iter, seek);
buflen -= seek;
}
len = sock_recvmsg(svsk->sk_sock, &msg, MSG_DONTWAIT);
if (len > 0)
svc_flush_bvec(bvec, len, seek);
/* If we read a full record, then assume there may be more
* data to read (stream based sockets only!)
*/
if (len == buflen)
set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
return len;
}
/*
* Set socket snd and rcv buffer lengths
*/
static void svc_sock_setbufsize(struct svc_sock *svsk, unsigned int nreqs)
{
unsigned int max_mesg = svsk->sk_xprt.xpt_server->sv_max_mesg;
struct socket *sock = svsk->sk_sock;
nreqs = min(nreqs, INT_MAX / 2 / max_mesg);
lock_sock(sock->sk);
sock->sk->sk_sndbuf = nreqs * max_mesg * 2;
sock->sk->sk_rcvbuf = nreqs * max_mesg * 2;
sock->sk->sk_write_space(sock->sk);
release_sock(sock->sk);
}
static void svc_sock_secure_port(struct svc_rqst *rqstp)
{
if (svc_port_is_privileged(svc_addr(rqstp)))
set_bit(RQ_SECURE, &rqstp->rq_flags);
else
clear_bit(RQ_SECURE, &rqstp->rq_flags);
}
/*
* INET callback when data has been received on the socket.
*/
static void svc_data_ready(struct sock *sk)
{
struct svc_sock *svsk = (struct svc_sock *)sk->sk_user_data;
if (svsk) {
/* Refer to svc_setup_socket() for details. */
rmb();
svsk->sk_odata(sk);
trace_svcsock_data_ready(&svsk->sk_xprt, 0);
if (!test_and_set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags))
svc_xprt_enqueue(&svsk->sk_xprt);
}
}
/*
* INET callback when space is newly available on the socket.
*/
static void svc_write_space(struct sock *sk)
{
struct svc_sock *svsk = (struct svc_sock *)(sk->sk_user_data);
if (svsk) {
/* Refer to svc_setup_socket() for details. */
rmb();
trace_svcsock_write_space(&svsk->sk_xprt, 0);
svsk->sk_owspace(sk);
svc_xprt_enqueue(&svsk->sk_xprt);
}
}
static int svc_tcp_has_wspace(struct svc_xprt *xprt)
{
struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
if (test_bit(XPT_LISTENER, &xprt->xpt_flags))
return 1;
return !test_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
}
static void svc_tcp_kill_temp_xprt(struct svc_xprt *xprt)
{
struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
sock_no_linger(svsk->sk_sock->sk);
}
/*
* See net/ipv6/ip_sockglue.c : ip_cmsg_recv_pktinfo
*/
static int svc_udp_get_dest_address4(struct svc_rqst *rqstp,
struct cmsghdr *cmh)
{
struct in_pktinfo *pki = CMSG_DATA(cmh);
struct sockaddr_in *daddr = svc_daddr_in(rqstp);
if (cmh->cmsg_type != IP_PKTINFO)
return 0;
daddr->sin_family = AF_INET;
daddr->sin_addr.s_addr = pki->ipi_spec_dst.s_addr;
return 1;
}
/*
* See net/ipv6/datagram.c : ip6_datagram_recv_ctl
*/
static int svc_udp_get_dest_address6(struct svc_rqst *rqstp,
struct cmsghdr *cmh)
{
struct in6_pktinfo *pki = CMSG_DATA(cmh);
struct sockaddr_in6 *daddr = svc_daddr_in6(rqstp);
if (cmh->cmsg_type != IPV6_PKTINFO)
return 0;
daddr->sin6_family = AF_INET6;
daddr->sin6_addr = pki->ipi6_addr;
daddr->sin6_scope_id = pki->ipi6_ifindex;
return 1;
}
/*
* Copy the UDP datagram's destination address to the rqstp structure.
* The 'destination' address in this case is the address to which the
* peer sent the datagram, i.e. our local address. For multihomed
* hosts, this can change from msg to msg. Note that only the IP
* address changes, the port number should remain the same.
*/
static int svc_udp_get_dest_address(struct svc_rqst *rqstp,
struct cmsghdr *cmh)
{
switch (cmh->cmsg_level) {
case SOL_IP:
return svc_udp_get_dest_address4(rqstp, cmh);
case SOL_IPV6:
return svc_udp_get_dest_address6(rqstp, cmh);
}
return 0;
}
/**
* svc_udp_recvfrom - Receive a datagram from a UDP socket.
* @rqstp: request structure into which to receive an RPC Call
*
* Called in a loop when XPT_DATA has been set.
*
* Returns:
* On success, the number of bytes in a received RPC Call, or
* %0 if a complete RPC Call message was not ready to return
*/
static int svc_udp_recvfrom(struct svc_rqst *rqstp)
{
struct svc_sock *svsk =
container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
struct svc_serv *serv = svsk->sk_xprt.xpt_server;
struct sk_buff *skb;
union {
struct cmsghdr hdr;
long all[SVC_PKTINFO_SPACE / sizeof(long)];
} buffer;
struct cmsghdr *cmh = &buffer.hdr;
struct msghdr msg = {
.msg_name = svc_addr(rqstp),
.msg_control = cmh,
.msg_controllen = sizeof(buffer),
.msg_flags = MSG_DONTWAIT,
};
size_t len;
int err;
if (test_and_clear_bit(XPT_CHNGBUF, &svsk->sk_xprt.xpt_flags))
/* udp sockets need large rcvbuf as all pending
* requests are still in that buffer. sndbuf must
* also be large enough that there is enough space
* for one reply per thread. We count all threads
* rather than threads in a particular pool, which
* provides an upper bound on the number of threads
* which will access the socket.
*/
svc_sock_setbufsize(svsk, serv->sv_nrthreads + 3);
clear_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
err = kernel_recvmsg(svsk->sk_sock, &msg, NULL,
0, 0, MSG_PEEK | MSG_DONTWAIT);
if (err < 0)
goto out_recv_err;
skb = skb_recv_udp(svsk->sk_sk, 0, 1, &err);
if (!skb)
goto out_recv_err;
len = svc_addr_len(svc_addr(rqstp));
rqstp->rq_addrlen = len;
if (skb->tstamp == 0) {
skb->tstamp = ktime_get_real();
/* Don't enable netstamp, sunrpc doesn't
need that much accuracy */
}
sock_write_timestamp(svsk->sk_sk, skb->tstamp);
set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags); /* there may be more data... */
len = skb->len;
rqstp->rq_arg.len = len;
trace_svcsock_udp_recv(&svsk->sk_xprt, len);
rqstp->rq_prot = IPPROTO_UDP;
if (!svc_udp_get_dest_address(rqstp, cmh))
goto out_cmsg_err;
rqstp->rq_daddrlen = svc_addr_len(svc_daddr(rqstp));
if (skb_is_nonlinear(skb)) {
/* we have to copy */
local_bh_disable();
if (csum_partial_copy_to_xdr(&rqstp->rq_arg, skb))
goto out_bh_enable;
local_bh_enable();
consume_skb(skb);
} else {
/* we can use it in-place */
rqstp->rq_arg.head[0].iov_base = skb->data;
rqstp->rq_arg.head[0].iov_len = len;
if (skb_checksum_complete(skb))
goto out_free;
rqstp->rq_xprt_ctxt = skb;
}
rqstp->rq_arg.page_base = 0;
if (len <= rqstp->rq_arg.head[0].iov_len) {
rqstp->rq_arg.head[0].iov_len = len;
rqstp->rq_arg.page_len = 0;
rqstp->rq_respages = rqstp->rq_pages+1;
} else {
rqstp->rq_arg.page_len = len - rqstp->rq_arg.head[0].iov_len;
rqstp->rq_respages = rqstp->rq_pages + 1 +
DIV_ROUND_UP(rqstp->rq_arg.page_len, PAGE_SIZE);
}
rqstp->rq_next_page = rqstp->rq_respages+1;
if (serv->sv_stats)
serv->sv_stats->netudpcnt++;
svc_xprt_received(rqstp->rq_xprt);
return len;
out_recv_err:
if (err != -EAGAIN) {
/* possibly an icmp error */
set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
}
trace_svcsock_udp_recv_err(&svsk->sk_xprt, err);
goto out_clear_busy;
out_cmsg_err:
net_warn_ratelimited("svc: received unknown control message %d/%d; dropping RPC reply datagram\n",
cmh->cmsg_level, cmh->cmsg_type);
goto out_free;
out_bh_enable:
local_bh_enable();
out_free:
kfree_skb(skb);
out_clear_busy:
svc_xprt_received(rqstp->rq_xprt);
return 0;
}
/**
* svc_udp_sendto - Send out a reply on a UDP socket
* @rqstp: completed svc_rqst
*
* xpt_mutex ensures @rqstp's whole message is written to the socket
* without interruption.
*
* Returns the number of bytes sent, or a negative errno.
*/
static int svc_udp_sendto(struct svc_rqst *rqstp)
{
struct svc_xprt *xprt = rqstp->rq_xprt;
struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
struct xdr_buf *xdr = &rqstp->rq_res;
union {
struct cmsghdr hdr;
long all[SVC_PKTINFO_SPACE / sizeof(long)];
} buffer;
struct cmsghdr *cmh = &buffer.hdr;
struct msghdr msg = {
.msg_name = &rqstp->rq_addr,
.msg_namelen = rqstp->rq_addrlen,
.msg_control = cmh,
.msg_controllen = sizeof(buffer),
};
unsigned int sent;
int err;
svc_udp_release_rqst(rqstp);
svc_set_cmsg_data(rqstp, cmh);
mutex_lock(&xprt->xpt_mutex);
if (svc_xprt_is_dead(xprt))
goto out_notconn;
err = xprt_sock_sendmsg(svsk->sk_sock, &msg, xdr, 0, 0, &sent);
xdr_free_bvec(xdr);
if (err == -ECONNREFUSED) {
/* ICMP error on earlier request. */
err = xprt_sock_sendmsg(svsk->sk_sock, &msg, xdr, 0, 0, &sent);
xdr_free_bvec(xdr);
}
trace_svcsock_udp_send(xprt, err);
mutex_unlock(&xprt->xpt_mutex);
if (err < 0)
return err;
return sent;
out_notconn:
mutex_unlock(&xprt->xpt_mutex);
return -ENOTCONN;
}
static int svc_udp_has_wspace(struct svc_xprt *xprt)
{
struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
struct svc_serv *serv = xprt->xpt_server;
unsigned long required;
/*
* Set the SOCK_NOSPACE flag before checking the available
* sock space.
*/
set_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
required = atomic_read(&svsk->sk_xprt.xpt_reserved) + serv->sv_max_mesg;
if (required*2 > sock_wspace(svsk->sk_sk))
return 0;
clear_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
return 1;
}
static struct svc_xprt *svc_udp_accept(struct svc_xprt *xprt)
{
BUG();
return NULL;
}
static void svc_udp_kill_temp_xprt(struct svc_xprt *xprt)
{
}
static struct svc_xprt *svc_udp_create(struct svc_serv *serv,
struct net *net,
struct sockaddr *sa, int salen,
int flags)
{
return svc_create_socket(serv, IPPROTO_UDP, net, sa, salen, flags);
}
static const struct svc_xprt_ops svc_udp_ops = {
.xpo_create = svc_udp_create,
.xpo_recvfrom = svc_udp_recvfrom,
.xpo_sendto = svc_udp_sendto,
.xpo_result_payload = svc_sock_result_payload,
.xpo_release_rqst = svc_udp_release_rqst,
.xpo_detach = svc_sock_detach,
.xpo_free = svc_sock_free,
.xpo_has_wspace = svc_udp_has_wspace,
.xpo_accept = svc_udp_accept,
.xpo_secure_port = svc_sock_secure_port,
.xpo_kill_temp_xprt = svc_udp_kill_temp_xprt,
};
static struct svc_xprt_class svc_udp_class = {
.xcl_name = "udp",
.xcl_owner = THIS_MODULE,
.xcl_ops = &svc_udp_ops,
.xcl_max_payload = RPCSVC_MAXPAYLOAD_UDP,
.xcl_ident = XPRT_TRANSPORT_UDP,
};
static void svc_udp_init(struct svc_sock *svsk, struct svc_serv *serv)
{
svc_xprt_init(sock_net(svsk->sk_sock->sk), &svc_udp_class,
&svsk->sk_xprt, serv);
clear_bit(XPT_CACHE_AUTH, &svsk->sk_xprt.xpt_flags);
svsk->sk_sk->sk_data_ready = svc_data_ready;
svsk->sk_sk->sk_write_space = svc_write_space;
/* initialise setting must have enough space to
* receive and respond to one request.
* svc_udp_recvfrom will re-adjust if necessary
*/
svc_sock_setbufsize(svsk, 3);
/* data might have come in before data_ready set up */
set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
set_bit(XPT_CHNGBUF, &svsk->sk_xprt.xpt_flags);
/* make sure we get destination address info */
switch (svsk->sk_sk->sk_family) {
case AF_INET:
ip_sock_set_pktinfo(svsk->sk_sock->sk);
break;
case AF_INET6:
ip6_sock_set_recvpktinfo(svsk->sk_sock->sk);
break;
default:
BUG();
}
}
/*
* A data_ready event on a listening socket means there's a connection
* pending. Do not use state_change as a substitute for it.
*/
static void svc_tcp_listen_data_ready(struct sock *sk)
{
struct svc_sock *svsk = (struct svc_sock *)sk->sk_user_data;
if (svsk) {
/* Refer to svc_setup_socket() for details. */
rmb();
svsk->sk_odata(sk);
}
/*
* This callback may called twice when a new connection
* is established as a child socket inherits everything
* from a parent LISTEN socket.
* 1) data_ready method of the parent socket will be called
* when one of child sockets become ESTABLISHED.
* 2) data_ready method of the child socket may be called
* when it receives data before the socket is accepted.
* In case of 2, we should ignore it silently.
*/
if (sk->sk_state == TCP_LISTEN) {
if (svsk) {
set_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags);
svc_xprt_enqueue(&svsk->sk_xprt);
}
}
}
/*
* A state change on a connected socket means it's dying or dead.
*/
static void svc_tcp_state_change(struct sock *sk)
{
struct svc_sock *svsk = (struct svc_sock *)sk->sk_user_data;
if (svsk) {
/* Refer to svc_setup_socket() for details. */
rmb();
svsk->sk_ostate(sk);
trace_svcsock_tcp_state(&svsk->sk_xprt, svsk->sk_sock);
if (sk->sk_state != TCP_ESTABLISHED)
svc_xprt_deferred_close(&svsk->sk_xprt);
}
}
/*
* Accept a TCP connection
*/
static struct svc_xprt *svc_tcp_accept(struct svc_xprt *xprt)
{
struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
struct sockaddr_storage addr;
struct sockaddr *sin = (struct sockaddr *) &addr;
struct svc_serv *serv = svsk->sk_xprt.xpt_server;
struct socket *sock = svsk->sk_sock;
struct socket *newsock;
struct svc_sock *newsvsk;
int err, slen;
if (!sock)
return NULL;
clear_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags);
err = kernel_accept(sock, &newsock, O_NONBLOCK);
if (err < 0) {
if (err == -ENOMEM)
printk(KERN_WARNING "%s: no more sockets!\n",
serv->sv_name);
else if (err != -EAGAIN)
net_warn_ratelimited("%s: accept failed (err %d)!\n",
serv->sv_name, -err);
trace_svcsock_accept_err(xprt, serv->sv_name, err);
return NULL;
}
set_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags);
err = kernel_getpeername(newsock, sin);
if (err < 0) {
trace_svcsock_getpeername_err(xprt, serv->sv_name, err);
goto failed; /* aborted connection or whatever */
}
slen = err;
/* Reset the inherited callbacks before calling svc_setup_socket */
newsock->sk->sk_state_change = svsk->sk_ostate;
newsock->sk->sk_data_ready = svsk->sk_odata;
newsock->sk->sk_write_space = svsk->sk_owspace;
/* make sure that a write doesn't block forever when
* low on memory
*/
newsock->sk->sk_sndtimeo = HZ*30;
newsvsk = svc_setup_socket(serv, newsock,
(SVC_SOCK_ANONYMOUS | SVC_SOCK_TEMPORARY));
if (IS_ERR(newsvsk))
goto failed;
svc_xprt_set_remote(&newsvsk->sk_xprt, sin, slen);
err = kernel_getsockname(newsock, sin);
slen = err;
if (unlikely(err < 0))
slen = offsetof(struct sockaddr, sa_data);
svc_xprt_set_local(&newsvsk->sk_xprt, sin, slen);
if (sock_is_loopback(newsock->sk))
set_bit(XPT_LOCAL, &newsvsk->sk_xprt.xpt_flags);
else
clear_bit(XPT_LOCAL, &newsvsk->sk_xprt.xpt_flags);
if (serv->sv_stats)
serv->sv_stats->nettcpconn++;
return &newsvsk->sk_xprt;
failed:
sock_release(newsock);
return NULL;
}
static size_t svc_tcp_restore_pages(struct svc_sock *svsk,
struct svc_rqst *rqstp)
{
size_t len = svsk->sk_datalen;
unsigned int i, npages;
if (!len)
return 0;
npages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
for (i = 0; i < npages; i++) {
if (rqstp->rq_pages[i] != NULL)
put_page(rqstp->rq_pages[i]);
BUG_ON(svsk->sk_pages[i] == NULL);
rqstp->rq_pages[i] = svsk->sk_pages[i];
svsk->sk_pages[i] = NULL;
}
rqstp->rq_arg.head[0].iov_base = page_address(rqstp->rq_pages[0]);
return len;
}
static void svc_tcp_save_pages(struct svc_sock *svsk, struct svc_rqst *rqstp)
{
unsigned int i, len, npages;
if (svsk->sk_datalen == 0)
return;
len = svsk->sk_datalen;
npages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
for (i = 0; i < npages; i++) {
svsk->sk_pages[i] = rqstp->rq_pages[i];
rqstp->rq_pages[i] = NULL;
}
}
static void svc_tcp_clear_pages(struct svc_sock *svsk)
{
unsigned int i, len, npages;
if (svsk->sk_datalen == 0)
goto out;
len = svsk->sk_datalen;
npages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
for (i = 0; i < npages; i++) {
if (svsk->sk_pages[i] == NULL) {
WARN_ON_ONCE(1);
continue;
}
put_page(svsk->sk_pages[i]);
svsk->sk_pages[i] = NULL;
}
out:
svsk->sk_tcplen = 0;
svsk->sk_datalen = 0;
}
/*
* Receive fragment record header into sk_marker.
*/
static ssize_t svc_tcp_read_marker(struct svc_sock *svsk,
struct svc_rqst *rqstp)
{
ssize_t want, len;
/* If we haven't gotten the record length yet,
* get the next four bytes.
*/
if (svsk->sk_tcplen < sizeof(rpc_fraghdr)) {
struct msghdr msg = { NULL };
struct kvec iov;
want = sizeof(rpc_fraghdr) - svsk->sk_tcplen;
iov.iov_base = ((char *)&svsk->sk_marker) + svsk->sk_tcplen;
iov.iov_len = want;
iov_iter_kvec(&msg.msg_iter, READ, &iov, 1, want);
len = sock_recvmsg(svsk->sk_sock, &msg, MSG_DONTWAIT);
if (len < 0)
return len;
svsk->sk_tcplen += len;
if (len < want) {
/* call again to read the remaining bytes */
goto err_short;
}
trace_svcsock_marker(&svsk->sk_xprt, svsk->sk_marker);
if (svc_sock_reclen(svsk) + svsk->sk_datalen >
svsk->sk_xprt.xpt_server->sv_max_mesg)
goto err_too_large;
}
return svc_sock_reclen(svsk);
err_too_large:
net_notice_ratelimited("svc: %s %s RPC fragment too large: %d\n",
__func__, svsk->sk_xprt.xpt_server->sv_name,
svc_sock_reclen(svsk));
svc_xprt_deferred_close(&svsk->sk_xprt);
err_short:
return -EAGAIN;
}
static int receive_cb_reply(struct svc_sock *svsk, struct svc_rqst *rqstp)
{
struct rpc_xprt *bc_xprt = svsk->sk_xprt.xpt_bc_xprt;
struct rpc_rqst *req = NULL;
struct kvec *src, *dst;
__be32 *p = (__be32 *)rqstp->rq_arg.head[0].iov_base;
__be32 xid;
__be32 calldir;
xid = *p++;
calldir = *p;
if (!bc_xprt)
return -EAGAIN;
spin_lock(&bc_xprt->queue_lock);
req = xprt_lookup_rqst(bc_xprt, xid);
if (!req)
goto unlock_notfound;
memcpy(&req->rq_private_buf, &req->rq_rcv_buf, sizeof(struct xdr_buf));
/*
* XXX!: cheating for now! Only copying HEAD.
* But we know this is good enough for now (in fact, for any
* callback reply in the forseeable future).
*/
dst = &req->rq_private_buf.head[0];
src = &rqstp->rq_arg.head[0];
if (dst->iov_len < src->iov_len)
goto unlock_eagain; /* whatever; just giving up. */
memcpy(dst->iov_base, src->iov_base, src->iov_len);
xprt_complete_rqst(req->rq_task, rqstp->rq_arg.len);
rqstp->rq_arg.len = 0;
spin_unlock(&bc_xprt->queue_lock);
return 0;
unlock_notfound:
printk(KERN_NOTICE
"%s: Got unrecognized reply: "
"calldir 0x%x xpt_bc_xprt %p xid %08x\n",
__func__, ntohl(calldir),
bc_xprt, ntohl(xid));
unlock_eagain:
spin_unlock(&bc_xprt->queue_lock);
return -EAGAIN;
}
static void svc_tcp_fragment_received(struct svc_sock *svsk)
{
/* If we have more data, signal svc_xprt_enqueue() to try again */
svsk->sk_tcplen = 0;
svsk->sk_marker = xdr_zero;
}
/**
* svc_tcp_recvfrom - Receive data from a TCP socket
* @rqstp: request structure into which to receive an RPC Call
*
* Called in a loop when XPT_DATA has been set.
*
* Read the 4-byte stream record marker, then use the record length
* in that marker to set up exactly the resources needed to receive
* the next RPC message into @rqstp.
*
* Returns:
* On success, the number of bytes in a received RPC Call, or
* %0 if a complete RPC Call message was not ready to return
*
* The zero return case handles partial receives and callback Replies.
* The state of a partial receive is preserved in the svc_sock for
* the next call to svc_tcp_recvfrom.
*/
static int svc_tcp_recvfrom(struct svc_rqst *rqstp)
{
struct svc_sock *svsk =
container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
struct svc_serv *serv = svsk->sk_xprt.xpt_server;
size_t want, base;
ssize_t len;
__be32 *p;
__be32 calldir;
clear_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
len = svc_tcp_read_marker(svsk, rqstp);
if (len < 0)
goto error;
base = svc_tcp_restore_pages(svsk, rqstp);
want = len - (svsk->sk_tcplen - sizeof(rpc_fraghdr));
len = svc_tcp_read_msg(rqstp, base + want, base);
if (len >= 0) {
trace_svcsock_tcp_recv(&svsk->sk_xprt, len);
svsk->sk_tcplen += len;