ClabureDB: Classified Bug-Reports Database

   /*
    * 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 <okir@monad.swb.de>
   */
  
  #include <linux/kernel.h>
  #include <linux/sched.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/tcp.h>
  #include <net/tcp_states.h>
  #include <asm/uaccess.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>
  
  #define RPCDBG_FACILITY        RPCDBG_SVCXPRT
  
  
  static struct svc_sock *svc_setup_socket(struct svc_serv *, struct socket *,
                                           int *errp, int flags);
  static void                svc_udp_data_ready(struct sock *, int);
  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_sock_free(struct svc_xprt *);
  
  static struct svc_xprt *svc_create_socket(struct svc_serv *, int,
                                            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;
          BUG_ON(sock_owned_by_user(sk));
          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
  
  /*
  * Release an skbuff after use
  */
 static void svc_release_skb(struct svc_rqst *rqstp)
 {
         struct sk_buff *skb = rqstp->rq_xprt_ctxt;
         struct svc_deferred_req *dr = rqstp->rq_deferred;
 
         if (skb) {
                 struct svc_sock *svsk =
                         container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
                 rqstp->rq_xprt_ctxt = NULL;
 
                 dprintk("svc: service %p, releasing skb %p\n", rqstp, skb);
                 skb_free_datagram(svsk->sk_sk, skb);
         }
         if (dr) {
                 rqstp->rq_deferred = NULL;
                 kfree(dr);
         }
 }
 
 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 = rqstp->rq_daddr.addr.s_addr;
                         cmh->cmsg_len = CMSG_LEN(sizeof(*pki));
                 }
                 break;
 
         case AF_INET6: {
                         struct in6_pktinfo *pki = CMSG_DATA(cmh);
 
                         cmh->cmsg_level = SOL_IPV6;
                         cmh->cmsg_type = IPV6_PKTINFO;
                         pki->ipi6_ifindex = 0;
                         ipv6_addr_copy(&pki->ipi6_addr,
                                         &rqstp->rq_daddr.addr6);
                         cmh->cmsg_len = CMSG_LEN(sizeof(*pki));
                 }
                 break;
         }
         return;
 }
 
 /*
  * Generic sendto routine
  */
 static int svc_sendto(struct svc_rqst *rqstp, struct xdr_buf *xdr)
 {
         struct svc_sock        *svsk =
                 container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
         struct socket        *sock = svsk->sk_sock;
         int                slen;
         union {
                 struct cmsghdr        hdr;
                 long                all[SVC_PKTINFO_SPACE / sizeof(long)];
         } buffer;
         struct cmsghdr *cmh = &buffer.hdr;
         int                len = 0;
         int                result;
         int                size;
         struct page        **ppage = xdr->pages;
         size_t                base = xdr->page_base;
         unsigned int        pglen = xdr->page_len;
         unsigned int        flags = MSG_MORE;
         RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
 
         slen = xdr->len;
 
         if (rqstp->rq_prot == IPPROTO_UDP) {
                 struct msghdr msg = {
                         .msg_name        = &rqstp->rq_addr,
                         .msg_namelen        = rqstp->rq_addrlen,
                         .msg_control        = cmh,
                         .msg_controllen        = sizeof(buffer),
                         .msg_flags        = MSG_MORE,
                 };
 
                 svc_set_cmsg_data(rqstp, cmh);
 
                 if (sock_sendmsg(sock, &msg, 0) < 0)
                         goto out;
         }
 
         /* send head */
         if (slen == xdr->head[0].iov_len)
                 flags = 0;
         len = kernel_sendpage(sock, rqstp->rq_respages[0], 0,
                                   xdr->head[0].iov_len, flags);
         if (len != xdr->head[0].iov_len)
                 goto out;
         slen -= xdr->head[0].iov_len;
         if (slen == 0)
                 goto out;
 
         /* send page data */
         size = PAGE_SIZE - base < pglen ? PAGE_SIZE - base : pglen;
         while (pglen > 0) {
                 if (slen == size)
                         flags = 0;
                 result = kernel_sendpage(sock, *ppage, base, size, flags);
                 if (result > 0)
                         len += result;
                 if (result != size)
                         goto out;
                 slen -= size;
                 pglen -= size;
                 size = PAGE_SIZE < pglen ? PAGE_SIZE : pglen;
                 base = 0;
                 ppage++;
         }
         /* send tail */
         if (xdr->tail[0].iov_len) {
                 result = kernel_sendpage(sock, rqstp->rq_respages[0],
                                              ((unsigned long)xdr->tail[0].iov_base)
                                                 & (PAGE_SIZE-1),
                                              xdr->tail[0].iov_len, 0);
 
                 if (result > 0)
                         len += result;
         }
 out:
         dprintk("svc: socket %p sendto([%p %Zu... ], %d) = %d (addr %s)\n",
                 svsk, xdr->head[0].iov_base, xdr->head[0].iov_len,
                 xdr->len, len, svc_print_addr(rqstp, buf, sizeof(buf)));
 
         return len;
 }
 
 /*
  * Report socket names for nfsdfs
  */
 static int one_sock_name(char *buf, struct svc_sock *svsk)
 {
         int len;
 
         switch(svsk->sk_sk->sk_family) {
         case AF_INET:
                 len = sprintf(buf, "ipv4 %s %u.%u.%u.%u %d\n",
                               svsk->sk_sk->sk_protocol==IPPROTO_UDP?
                               "udp" : "tcp",
                               NIPQUAD(inet_sk(svsk->sk_sk)->rcv_saddr),
                               inet_sk(svsk->sk_sk)->num);
                 break;
         default:
                 len = sprintf(buf, "*unknown-%d*\n",
                                svsk->sk_sk->sk_family);
         }
         return len;
 }
 
 int
 svc_sock_names(char *buf, struct svc_serv *serv, char *toclose)
 {
         struct svc_sock *svsk, *closesk = NULL;
         int len = 0;
 
         if (!serv)
                 return 0;
         spin_lock_bh(&serv->sv_lock);
         list_for_each_entry(svsk, &serv->sv_permsocks, sk_xprt.xpt_list) {
                 int onelen = one_sock_name(buf+len, svsk);
                 if (toclose && strcmp(toclose, buf+len) == 0)
                         closesk = svsk;
                 else
                         len += onelen;
         }
         spin_unlock_bh(&serv->sv_lock);
         if (closesk)
                 /* Should unregister with portmap, but you cannot
                  * unregister just one protocol...
                  */
                 svc_close_xprt(&closesk->sk_xprt);
         else if (toclose)
                 return -ENOENT;
         return len;
 }
 EXPORT_SYMBOL(svc_sock_names);
 
 /*
  * Check input queue length
  */
 static int svc_recv_available(struct svc_sock *svsk)
 {
         struct socket        *sock = svsk->sk_sock;
         int                avail, err;
 
         err = kernel_sock_ioctl(sock, TIOCINQ, (unsigned long) &avail);
 
         return (err >= 0)? avail : err;
 }
 
 /*
  * Generic recvfrom routine.
  */
 static int svc_recvfrom(struct svc_rqst *rqstp, struct kvec *iov, int nr,
                         int buflen)
 {
         struct svc_sock *svsk =
                 container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
         struct msghdr msg = {
                 .msg_flags        = MSG_DONTWAIT,
         };
         int len;
 
         rqstp->rq_xprt_hlen = 0;
 
         len = kernel_recvmsg(svsk->sk_sock, &msg, iov, nr, buflen,
                                 msg.msg_flags);
 
         dprintk("svc: socket %p recvfrom(%p, %Zu) = %d\n",
                 svsk, iov[0].iov_base, iov[0].iov_len, len);
         return len;
 }
 
 /*
  * Set socket snd and rcv buffer lengths
  */
 static void svc_sock_setbufsize(struct socket *sock, unsigned int snd,
                                 unsigned int rcv)
 {
 #if 0
         mm_segment_t        oldfs;
         oldfs = get_fs(); set_fs(KERNEL_DS);
         sock_setsockopt(sock, SOL_SOCKET, SO_SNDBUF,
                         (char*)&snd, sizeof(snd));
         sock_setsockopt(sock, SOL_SOCKET, SO_RCVBUF,
                         (char*)&rcv, sizeof(rcv));
 #else
         /* sock_setsockopt limits use to sysctl_?mem_max,
          * which isn't acceptable.  Until that is made conditional
          * on not having CAP_SYS_RESOURCE or similar, we go direct...
          * DaveM said I could!
          */
         lock_sock(sock->sk);
         sock->sk->sk_sndbuf = snd * 2;
         sock->sk->sk_rcvbuf = rcv * 2;
         sock->sk->sk_userlocks |= SOCK_SNDBUF_LOCK|SOCK_RCVBUF_LOCK;
         release_sock(sock->sk);
 #endif
 }
 /*
  * INET callback when data has been received on the socket.
  */
 static void svc_udp_data_ready(struct sock *sk, int count)
 {
         struct svc_sock        *svsk = (struct svc_sock *)sk->sk_user_data;
 
         if (svsk) {
                 dprintk("svc: socket %p(inet %p), count=%d, busy=%d\n",
                         svsk, sk, count,
                         test_bit(XPT_BUSY, &svsk->sk_xprt.xpt_flags));
                 set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
                 svc_xprt_enqueue(&svsk->sk_xprt);
         }
         if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
                 wake_up_interruptible(sk->sk_sleep);
 }
 
 /*
  * 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) {
                 dprintk("svc: socket %p(inet %p), write_space busy=%d\n",
                         svsk, sk, test_bit(XPT_BUSY, &svsk->sk_xprt.xpt_flags));
                 svc_xprt_enqueue(&svsk->sk_xprt);
         }
 
         if (sk->sk_sleep && waitqueue_active(sk->sk_sleep)) {
                 dprintk("RPC svc_write_space: someone sleeping on %p\n",
                        svsk);
                 wake_up_interruptible(sk->sk_sleep);
         }
 }
 
 /*
  * 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 void svc_udp_get_dest_address(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);
                 rqstp->rq_daddr.addr.s_addr = pki->ipi_spec_dst.s_addr;
                 break;
                 }
         case AF_INET6: {
                 struct in6_pktinfo *pki = CMSG_DATA(cmh);
                 ipv6_addr_copy(&rqstp->rq_daddr.addr6, &pki->ipi6_addr);
                 break;
                 }
         }
 }
 
 /*
  * Receive a datagram from a UDP socket.
  */
 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;
         int                err, len;
         struct msghdr msg = {
                 .msg_name = svc_addr(rqstp),
                 .msg_control = cmh,
                 .msg_controllen = sizeof(buffer),
                 .msg_flags = MSG_DONTWAIT,
         };
 
         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->sk_sock,
                                 (serv->sv_nrthreads+3) * serv->sv_max_mesg,
                                 (serv->sv_nrthreads+3) * serv->sv_max_mesg);
 
         clear_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
         skb = NULL;
         err = kernel_recvmsg(svsk->sk_sock, &msg, NULL,
                              0, 0, MSG_PEEK | MSG_DONTWAIT);
         if (err >= 0)
                 skb = skb_recv_datagram(svsk->sk_sk, 0, 1, &err);
 
         if (skb == NULL) {
                 if (err != -EAGAIN) {
                         /* possibly an icmp error */
                         dprintk("svc: recvfrom returned error %d\n", -err);
                         set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
                 }
                 svc_xprt_received(&svsk->sk_xprt);
                 return -EAGAIN;
         }
         len = svc_addr_len(svc_addr(rqstp));
         if (len < 0)
                 return len;
         rqstp->rq_addrlen = len;
         if (skb->tstamp.tv64 == 0) {
                 skb->tstamp = ktime_get_real();
                 /* Don't enable netstamp, sunrpc doesn't
                    need that much accuracy */
         }
         svsk->sk_sk->sk_stamp = skb->tstamp;
         set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags); /* there may be more data... */
 
         /*
          * Maybe more packets - kick another thread ASAP.
          */
         svc_xprt_received(&svsk->sk_xprt);
 
         len  = skb->len - sizeof(struct udphdr);
         rqstp->rq_arg.len = len;
 
         rqstp->rq_prot = IPPROTO_UDP;
 
         if (cmh->cmsg_level != IPPROTO_IP ||
             cmh->cmsg_type != IP_PKTINFO) {
                 if (net_ratelimit())
                         printk("rpcsvc: received unknown control message:"
                                "%d/%d\n",
                                cmh->cmsg_level, cmh->cmsg_type);
                 skb_free_datagram(svsk->sk_sk, skb);
                 return 0;
         }
         svc_udp_get_dest_address(rqstp, cmh);
 
         if (skb_is_nonlinear(skb)) {
                 /* we have to copy */
                 local_bh_disable();
                 if (csum_partial_copy_to_xdr(&rqstp->rq_arg, skb)) {
                         local_bh_enable();
                         /* checksum error */
                         skb_free_datagram(svsk->sk_sk, skb);
                         return 0;
                 }
                 local_bh_enable();
                 skb_free_datagram(svsk->sk_sk, skb);
         } else {
                 /* we can use it in-place */
                 rqstp->rq_arg.head[0].iov_base = skb->data +
                         sizeof(struct udphdr);
                 rqstp->rq_arg.head[0].iov_len = len;
                 if (skb_checksum_complete(skb)) {
                         skb_free_datagram(svsk->sk_sk, skb);
                         return 0;
                 }
                 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);
         }
 
         if (serv->sv_stats)
                 serv->sv_stats->netudpcnt++;
 
         return len;
 }
 
 static int
 svc_udp_sendto(struct svc_rqst *rqstp)
 {
         int                error;
 
         error = svc_sendto(rqstp, &rqstp->rq_res);
         if (error == -ECONNREFUSED)
                 /* ICMP error on earlier request. */
                 error = svc_sendto(rqstp, &rqstp->rq_res);
 
         return error;
 }
 
 static void svc_udp_prep_reply_hdr(struct svc_rqst *rqstp)
 {
 }
 
 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 struct svc_xprt *svc_udp_create(struct svc_serv *serv,
                                        struct sockaddr *sa, int salen,
                                        int flags)
 {
         return svc_create_socket(serv, IPPROTO_UDP, sa, salen, flags);
 }
 
 static struct svc_xprt_ops svc_udp_ops = {
         .xpo_create = svc_udp_create,
         .xpo_recvfrom = svc_udp_recvfrom,
         .xpo_sendto = svc_udp_sendto,
         .xpo_release_rqst = svc_release_skb,
         .xpo_detach = svc_sock_detach,
         .xpo_free = svc_sock_free,
         .xpo_prep_reply_hdr = svc_udp_prep_reply_hdr,
         .xpo_has_wspace = svc_udp_has_wspace,
         .xpo_accept = svc_udp_accept,
 };
 
 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,
 };
 
 static void svc_udp_init(struct svc_sock *svsk, struct svc_serv *serv)
 {
         int one = 1;
         mm_segment_t oldfs;
 
         svc_xprt_init(&svc_udp_class, &svsk->sk_xprt, serv);
         clear_bit(XPT_CACHE_AUTH, &svsk->sk_xprt.xpt_flags);
         svsk->sk_sk->sk_data_ready = svc_udp_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->sk_sock,
                             3 * svsk->sk_xprt.xpt_server->sv_max_mesg,
                             3 * svsk->sk_xprt.xpt_server->sv_max_mesg);
 
         /* 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);
 
         oldfs = get_fs();
         set_fs(KERNEL_DS);
         /* make sure we get destination address info */
         svsk->sk_sock->ops->setsockopt(svsk->sk_sock, IPPROTO_IP, IP_PKTINFO,
                                        (char __user *)&one, sizeof(one));
         set_fs(oldfs);
 }
 
 /*
  * 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, int count_unused)
 {
         struct svc_sock        *svsk = (struct svc_sock *)sk->sk_user_data;
 
         dprintk("svc: socket %p TCP (listen) state change %d\n",
                 sk, sk->sk_state);
 
         /*
          * 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);
                 } else
                         printk("svc: socket %p: no user data\n", sk);
         }
 
         if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
                 wake_up_interruptible_all(sk->sk_sleep);
 }
 
 /*
  * 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;
 
         dprintk("svc: socket %p TCP (connected) state change %d (svsk %p)\n",
                 sk, sk->sk_state, sk->sk_user_data);
 
         if (!svsk)
                 printk("svc: socket %p: no user data\n", sk);
         else {
                 set_bit(XPT_CLOSE, &svsk->sk_xprt.xpt_flags);
                 svc_xprt_enqueue(&svsk->sk_xprt);
         }
         if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
                 wake_up_interruptible_all(sk->sk_sleep);
 }
 
 static void svc_tcp_data_ready(struct sock *sk, int count)
 {
         struct svc_sock *svsk = (struct svc_sock *)sk->sk_user_data;
 
         dprintk("svc: socket %p TCP data ready (svsk %p)\n",
                 sk, sk->sk_user_data);
         if (svsk) {
                 set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
                 svc_xprt_enqueue(&svsk->sk_xprt);
         }
         if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
                 wake_up_interruptible(sk->sk_sleep);
 }
 
 /*
  * 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;
         RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
 
         dprintk("svc: tcp_accept %p sock %p\n", svsk, sock);
         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_ratelimit())
                         printk(KERN_WARNING "%s: accept failed (err %d)!\n",
                                    serv->sv_name, -err);
                 return NULL;
         }
         set_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags);
 
         err = kernel_getpeername(newsock, sin, &slen);
         if (err < 0) {
                 if (net_ratelimit())
                         printk(KERN_WARNING "%s: peername failed (err %d)!\n",
                                    serv->sv_name, -err);
                 goto failed;                /* aborted connection or whatever */
         }
 
         /* Ideally, we would want to reject connections from unauthorized
          * hosts here, but when we get encryption, the IP of the host won't
          * tell us anything.  For now just warn about unpriv connections.
          */
         if (!svc_port_is_privileged(sin)) {
                 dprintk(KERN_WARNING
                         "%s: connect from unprivileged port: %s\n",
                         serv->sv_name,
                         __svc_print_addr(sin, buf, sizeof(buf)));
         }
         dprintk("%s: connect from %s\n", serv->sv_name,
                 __svc_print_addr(sin, buf, sizeof(buf)));
 
         /* make sure that a write doesn't block forever when
          * low on memory
          */
         newsock->sk->sk_sndtimeo = HZ*30;
 
         if (!(newsvsk = svc_setup_socket(serv, newsock, &err,
                                  (SVC_SOCK_ANONYMOUS | SVC_SOCK_TEMPORARY))))
                 goto failed;
         svc_xprt_set_remote(&newsvsk->sk_xprt, sin, slen);
         err = kernel_getsockname(newsock, sin, &slen);
         if (unlikely(err < 0)) {
                 dprintk("svc_tcp_accept: kernel_getsockname error %d\n", -err);
                 slen = offsetof(struct sockaddr, sa_data);
         }
         svc_xprt_set_local(&newsvsk->sk_xprt, sin, slen);
 
         if (serv->sv_stats)
                 serv->sv_stats->nettcpconn++;
 
         return &newsvsk->sk_xprt;
 
 failed:
         sock_release(newsock);
         return NULL;
 }
 
 /*
  * Receive data from a TCP socket.
  */
 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;
         int                len;
         struct kvec *vec;
         int pnum, vlen;
 
         dprintk("svc: tcp_recv %p data %d conn %d close %d\n",
                 svsk, test_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags),
                 test_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags),
                 test_bit(XPT_CLOSE, &svsk->sk_xprt.xpt_flags));
 
         if (test_and_clear_bit(XPT_CHNGBUF, &svsk->sk_xprt.xpt_flags))
                 /* sndbuf needs to have room for one request
                  * per thread, otherwise we can stall even when the
                  * network isn't a bottleneck.
                  *
                  * 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.
                  *
                  * rcvbuf just needs to be able to hold a few requests.
                  * Normally they will be removed from the queue
                  * as soon a a complete request arrives.
                  */
                 svc_sock_setbufsize(svsk->sk_sock,
                                     (serv->sv_nrthreads+3) * serv->sv_max_mesg,
                                     3 * serv->sv_max_mesg);
 
         clear_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
 
         /* Receive data. If we haven't got the record length yet, get
          * the next four bytes. Otherwise try to gobble up as much as
          * possible up to the complete record length.
          */
         if (svsk->sk_tcplen < sizeof(rpc_fraghdr)) {
                 int                want = sizeof(rpc_fraghdr) - svsk->sk_tcplen;
                 struct kvec        iov;
 
                 iov.iov_base = ((char *) &svsk->sk_reclen) + svsk->sk_tcplen;
                 iov.iov_len  = want;
                 if ((len = svc_recvfrom(rqstp, &iov, 1, want)) < 0)
                         goto error;
                 svsk->sk_tcplen += len;
 
                 if (len < want) {
                         dprintk("svc: short recvfrom while reading record "
                                 "length (%d of %d)\n", len, want);
                         svc_xprt_received(&svsk->sk_xprt);
                         return -EAGAIN; /* record header not complete */
                 }
 
                 svsk->sk_reclen = ntohl(svsk->sk_reclen);
                 if (!(svsk->sk_reclen & RPC_LAST_STREAM_FRAGMENT)) {
                         /* FIXME: technically, a record can be fragmented,
                          *  and non-terminal fragments will not have the top
                          *  bit set in the fragment length header.
                          *  But apparently no known nfs clients send fragmented
                          *  records. */
                         if (net_ratelimit())
                                 printk(KERN_NOTICE "RPC: multiple fragments "
                                         "per record not supported\n");
                         goto err_delete;
                 }
                 svsk->sk_reclen &= RPC_FRAGMENT_SIZE_MASK;
                 dprintk("svc: TCP record, %d bytes\n", svsk->sk_reclen);
                 if (svsk->sk_reclen > serv->sv_max_mesg) {
                         if (net_ratelimit())
                                 printk(KERN_NOTICE "RPC: "
                                         "fragment too large: 0x%08lx\n",
                                         (unsigned long)svsk->sk_reclen);
                         goto err_delete;
                 }
         }
 
         /* Check whether enough data is available */
         len = svc_recv_available(svsk);
         if (len < 0)
                 goto error;
 
         if (len < svsk->sk_reclen) {
                 dprintk("svc: incomplete TCP record (%d of %d)\n",
                         len, svsk->sk_reclen);
                 svc_xprt_received(&svsk->sk_xprt);
                 return -EAGAIN;        /* record not complete */
         }
         len = svsk->sk_reclen;
         set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
 
         vec = rqstp->rq_vec;
         vec[0] = rqstp->rq_arg.head[0];
         vlen = PAGE_SIZE;
         pnum = 1;
         while (vlen < len) {
                 vec[pnum].iov_base = page_address(rqstp->rq_pages[pnum]);
                 vec[pnum].iov_len = PAGE_SIZE;
                 pnum++;
                 vlen += PAGE_SIZE;
         }
         rqstp->rq_respages = &rqstp->rq_pages[pnum];
 
         /* Now receive data */
         len = svc_recvfrom(rqstp, vec, pnum, len);
         if (len < 0)
                 goto error;
 
         dprintk("svc: TCP complete record (%d bytes)\n", len);
         rqstp->rq_arg.len = len;
         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;
         } else {
                 rqstp->rq_arg.page_len = len - rqstp->rq_arg.head[0].iov_len;
         }
 
         rqstp->rq_xprt_ctxt   = NULL;
         rqstp->rq_prot              = IPPROTO_TCP;
 
         /* Reset TCP read info */
         svsk->sk_reclen = 0;
         svsk->sk_tcplen = 0;
 
         svc_xprt_copy_addrs(rqstp, &svsk->sk_xprt);
         svc_xprt_received(&svsk->sk_xprt);
         if (serv->sv_stats)
                 serv->sv_stats->nettcpcnt++;
 
         return len;
 
  err_delete:
         set_bit(XPT_CLOSE, &svsk->sk_xprt.xpt_flags);
         return -EAGAIN;
 
  error:
         if (len == -EAGAIN) {
                 dprintk("RPC: TCP recvfrom got EAGAIN\n");
                 svc_xprt_received(&svsk->sk_xprt);
         } else {
                 printk(KERN_NOTICE "%s: recvfrom returned errno %d\n",
                        svsk->sk_xprt.xpt_server->sv_name, -len);
                 goto err_delete;
         }
 
         return len;
 }
 
 /*
  * Send out data on TCP socket.
  */
 static int svc_tcp_sendto(struct svc_rqst *rqstp)
 {
         struct xdr_buf        *xbufp = &rqstp->rq_res;
         int sent;
         __be32 reclen;
 
         /* Set up the first element of the reply kvec.
          * Any other kvecs that may be in use have been taken
          * care of by the server implementation itself.
          */
         reclen = htonl(0x80000000|((xbufp->len ) - 4));
         memcpy(xbufp->head[0].iov_base, &reclen, 4);
 
         if (test_bit(XPT_DEAD, &rqstp->rq_xprt->xpt_flags))
                 return -ENOTCONN;
 
         sent = svc_sendto(rqstp, &rqstp->rq_res);
         if (sent != xbufp->len) {
                 printk(KERN_NOTICE
                        "rpc-srv/tcp: %s: %s %d when sending %d bytes "
                        "- shutting down socket\n",
                        rqstp->rq_xprt->xpt_server->sv_name,
                        (sent<0)?"got error":"sent only",
                        sent, xbufp->len);
                 set_bit(XPT_CLOSE, &rqstp->rq_xprt->xpt_flags);
                 svc_xprt_enqueue(rqstp->rq_xprt);
                 sent = -EAGAIN;
         }
         return sent;
 }
 
 /*
  * Setup response header. TCP has a 4B record length field.
  */
 static void svc_tcp_prep_reply_hdr(struct svc_rqst *rqstp)
 {
         struct kvec *resv = &rqstp->rq_res.head[0];
 
         /* tcp needs a space for the record length... */
         svc_putnl(resv, 0);
 }
 
 static int svc_tcp_has_wspace(struct svc_xprt *xprt)
 {
         struct svc_sock *svsk =        container_of(xprt, struct svc_sock, sk_xprt);
         struct svc_serv        *serv = svsk->sk_xprt.xpt_server;
         int required;
         int wspace;
 
         /*
          * 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;
         wspace = sk_stream_wspace(svsk->sk_sk);
 
         if (wspace < sk_stream_min_wspace(svsk->sk_sk))
                return 0;
        if (required * 2 > wspace)
                return 0;

        clear_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
        return 1;
}

static struct svc_xprt *svc_tcp_create(struct svc_serv *serv,
                                       struct sockaddr *sa, int salen,
                                       int flags)
{
        return svc_create_socket(serv, IPPROTO_TCP, sa, salen, flags);
}

static struct svc_xprt_ops svc_tcp_ops = {
        .xpo_create = svc_tcp_create,
        .xpo_recvfrom = svc_tcp_recvfrom,
        .xpo_sendto = svc_tcp_sendto,
        .xpo_release_rqst = svc_release_skb,
        .xpo_detach = svc_sock_detach,
        .xpo_free = svc_sock_free,
        .xpo_prep_reply_hdr = svc_tcp_prep_reply_hdr,
        .xpo_has_wspace = svc_tcp_has_wspace,
        .xpo_accept = svc_tcp_accept,
};

static struct svc_xprt_class svc_tcp_class = {
        .xcl_name = "tcp",
        .xcl_owner = THIS_MODULE,
        .xcl_ops = &svc_tcp_ops,
        .xcl_max_payload = RPCSVC_MAXPAYLOAD_TCP,
};

void svc_init_xprt_sock(void)
{
        svc_reg_xprt_class(&svc_tcp_class);
        svc_reg_xprt_class(&svc_udp_class);
}

void svc_cleanup_xprt_sock(void)
{
        svc_unreg_xprt_class(&svc_tcp_class);
        svc_unreg_xprt_class(&svc_udp_class);
}

static void svc_tcp_init(struct svc_sock *svsk, struct svc_serv *serv)
{
        struct sock        *sk = svsk->sk_sk;

        svc_xprt_init(&svc_tcp_class, &svsk->sk_xprt, serv);
        set_bit(XPT_CACHE_AUTH, &svsk->sk_xprt.xpt_flags);
        if (sk->sk_state == TCP_LISTEN) {
                dprintk("setting up TCP socket for listening\n");
                set_bit(XPT_LISTENER, &svsk->sk_xprt.xpt_flags);
                sk->sk_data_ready = svc_tcp_listen_data_ready;
                set_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags);
        } else {
                dprintk("setting up TCP socket for reading\n");
                sk->sk_state_change = svc_tcp_state_change;
                sk->sk_data_ready = svc_tcp_data_ready;
                sk->sk_write_space = svc_write_space;

                svsk->sk_reclen = 0;
                svsk->sk_tcplen = 0;

                tcp_sk(sk)->nonagle |= TCP_NAGLE_OFF;

                /* initialise setting must have enough space to
                 * receive and respond to one request.
                 * svc_tcp_recvfrom will re-adjust if necessary
                 */
                svc_sock_setbufsize(svsk->sk_sock,
                                    3 * svsk->sk_xprt.xpt_server->sv_max_mesg,
                                    3 * svsk->sk_xprt.xpt_server->sv_max_mesg);

                set_bit(XPT_CHNGBUF, &svsk->sk_xprt.xpt_flags);
                set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
                if (sk->sk_state != TCP_ESTABLISHED)
                        set_bit(XPT_CLOSE, &svsk->sk_xprt.xpt_flags);
        }
}

void svc_sock_update_bufs(struct svc_serv *serv)
{
        /*
         * The number of server threads has changed. Update
         * rcvbuf and sndbuf accordingly on all sockets
         */
        struct list_head *le;

        spin_lock_bh(&serv->sv_lock);
        list_for_each(le, &serv->sv_permsocks) {
                struct svc_sock *svsk =
                        list_entry(le, struct svc_sock, sk_xprt.xpt_list);
                set_bit(XPT_CHNGBUF, &svsk->sk_xprt.xpt_flags);
        }
        list_for_each(le, &serv->sv_tempsocks) {
                struct svc_sock *svsk =
                        list_entry(le, struct svc_sock, sk_xprt.xpt_list);
                set_bit(XPT_CHNGBUF, &svsk->sk_xprt.xpt_flags);
        }
        spin_unlock_bh(&serv->sv_lock);
}
EXPORT_SYMBOL(svc_sock_update_bufs);

/*
 * Initialize socket for RPC use and create svc_sock struct
 * XXX: May want to setsockopt SO_SNDBUF and SO_RCVBUF.
 */
static struct svc_sock *svc_setup_socket(struct svc_serv *serv,
                                                struct socket *sock,
                                                int *errp, int flags)
{
        struct svc_sock        *svsk;
        struct sock        *inet;
        int                pmap_register = !(flags & SVC_SOCK_ANONYMOUS);
        int                val;

        dprintk("svc: svc_setup_socket %p\n", sock);
        if (!(svsk = kzalloc(sizeof(*svsk), GFP_KERNEL))) {
                *errp = -ENOMEM;
                return NULL;
        }

        inet = sock->sk;

        /* Register socket with portmapper */
        if (*errp >= 0 && pmap_register)
                *errp = svc_register(serv, inet->sk_protocol,
                                     ntohs(inet_sk(inet)->sport));

        if (*errp < 0) {
                kfree(svsk);
                return NULL;
        }

        inet->sk_user_data = svsk;
        svsk->sk_sock = sock;
        svsk->sk_sk = inet;
        svsk->sk_ostate = inet->sk_state_change;
        svsk->sk_odata = inet->sk_data_ready;
        svsk->sk_owspace = inet->sk_write_space;

        /* Initialize the socket */
        if (sock->type == SOCK_DGRAM)
                svc_udp_init(svsk, serv);
        else
                svc_tcp_init(svsk, serv);

        /*
         * We start one listener per sv_serv.  We want AF_INET
         * requests to be automatically shunted to our AF_INET6
         * listener using a mapped IPv4 address.  Make sure
         * no-one starts an equivalent IPv4 listener, which
         * would steal our incoming connections.
         */
        val = 0;
        if (serv->sv_family == AF_INET6)
                kernel_setsockopt(sock, SOL_IPV6, IPV6_V6ONLY,
                                        (char *)&val, sizeof(val));

        dprintk("svc: svc_setup_socket created %p (inet %p)\n",
                                svsk, svsk->sk_sk);

        return svsk;
}

int svc_addsock(struct svc_serv *serv,
                int fd,
                char *name_return)
{
        int err = 0;
        struct socket *so = sockfd_lookup(fd, &err);
        struct svc_sock *svsk = NULL;

        if (!so)
                return err;
        if (so->sk->sk_family != AF_INET)
                err =  -EAFNOSUPPORT;
        else if (so->sk->sk_protocol != IPPROTO_TCP &&
            so->sk->sk_protocol != IPPROTO_UDP)
                err =  -EPROTONOSUPPORT;
        else if (so->state > SS_UNCONNECTED)
                err = -EISCONN;
        else {
                if (!try_module_get(THIS_MODULE))
                        err = -ENOENT;
                else
                        svsk = svc_setup_socket(serv, so, &err,
                                                SVC_SOCK_DEFAULTS);
                if (svsk) {
                        struct sockaddr_storage addr;
                        struct sockaddr *sin = (struct sockaddr *)&addr;
                        int salen;
                        if (kernel_getsockname(svsk->sk_sock, sin, &salen) == 0)
                                svc_xprt_set_local(&svsk->sk_xprt, sin, salen);
                        clear_bit(XPT_TEMP, &svsk->sk_xprt.xpt_flags);
                        spin_lock_bh(&serv->sv_lock);
                        list_add(&svsk->sk_xprt.xpt_list, &serv->sv_permsocks);
                        spin_unlock_bh(&serv->sv_lock);
                        svc_xprt_received(&svsk->sk_xprt);
                        err = 0;
                } else
                        module_put(THIS_MODULE);
        }
        if (err) {
                sockfd_put(so);
                return err;
        }
        return one_sock_name(name_return, svsk);
}
EXPORT_SYMBOL_GPL(svc_addsock);

/*
 * Create socket for RPC service.
 */
static struct svc_xprt *svc_create_socket(struct svc_serv *serv,
                                          int protocol,
                                          struct sockaddr *sin, int len,
                                          int flags)
{
        struct svc_sock        *svsk;
        struct socket        *sock;
        int                error;
        int                type;
        struct sockaddr_storage addr;
        struct sockaddr *newsin = (struct sockaddr *)&addr;
        int                newlen;
        RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);

        dprintk("svc: svc_create_socket(%s, %d, %s)\n",
                        serv->sv_program->pg_name, protocol,
                        __svc_print_addr(sin, buf, sizeof(buf)));

        if (protocol != IPPROTO_UDP && protocol != IPPROTO_TCP) {
                printk(KERN_WARNING "svc: only UDP and TCP "
                                "sockets supported\n");
                return ERR_PTR(-EINVAL);
        }
        type = (protocol == IPPROTO_UDP)? SOCK_DGRAM : SOCK_STREAM;

        error = sock_create_kern(sin->sa_family, type, protocol, &sock);
        if (error < 0)
                return ERR_PTR(error);

        svc_reclassify_socket(sock);

        if (type == SOCK_STREAM)
                sock->sk->sk_reuse = 1;                /* allow address reuse */
        error = kernel_bind(sock, sin, len);
        if (error < 0)
                goto bummer;

        newlen = len;
        error = kernel_getsockname(sock, newsin, &newlen);
        if (error < 0)
                goto bummer;

        if (protocol == IPPROTO_TCP) {
                if ((error = kernel_listen(sock, 64)) < 0)
                        goto bummer;
        }

        if ((svsk = svc_setup_socket(serv, sock, &error, flags)) != NULL) {
                svc_xprt_set_local(&svsk->sk_xprt, newsin, newlen);
                return (struct svc_xprt *)svsk;
        }

bummer:
        dprintk("svc: svc_create_socket error = %d\n", -error);
        sock_release(sock);
        return ERR_PTR(error);
}

/*
 * Detach the svc_sock from the socket so that no
 * more callbacks occur.
 */
static void svc_sock_detach(struct svc_xprt *xprt)
{
        struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
        struct sock *sk = svsk->sk_sk;

        dprintk("svc: svc_sock_detach(%p)\n", svsk);

        /* put back the old socket callbacks */
        sk->sk_state_change = svsk->sk_ostate;
        sk->sk_data_ready = svsk->sk_odata;
        sk->sk_write_space = svsk->sk_owspace;
}

/*
 * Free the svc_sock's socket resources and the svc_sock itself.
 */
static void svc_sock_free(struct svc_xprt *xprt)
{
        struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
        dprintk("svc: svc_sock_free(%p)\n", svsk);

        if (svsk->sk_sock->file)
                sockfd_put(svsk->sk_sock);
        else
                sock_release(svsk->sk_sock);
        kfree(svsk);
}