nfsd41: sunrpc: Added rpc server-side backchannel handling
[GitHub/moto-9609/android_kernel_motorola_exynos9610.git] / net / sunrpc / svcsock.c
index 76a380d37de4decb4ee1f4ac16482baef1133367..ccc5e83cae5d25cf592237025167d6d1b9d9c7bd 100644 (file)
@@ -49,6 +49,7 @@
 #include <linux/sunrpc/msg_prot.h>
 #include <linux/sunrpc/svcsock.h>
 #include <linux/sunrpc/stats.h>
+#include <linux/sunrpc/xprt.h>
 
 #define RPCDBG_FACILITY        RPCDBG_SVCXPRT
 
@@ -153,49 +154,27 @@ static void svc_set_cmsg_data(struct svc_rqst *rqstp, struct cmsghdr *cmh)
 }
 
 /*
- * Generic sendto routine
+ * send routine intended to be shared by the fore- and back-channel
  */
-static int svc_sendto(struct svc_rqst *rqstp, struct xdr_buf *xdr)
+int svc_send_common(struct socket *sock, struct xdr_buf *xdr,
+                   struct page *headpage, unsigned long headoffset,
+                   struct page *tailpage, unsigned long tailoffset)
 {
-       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]);
+       int             slen;
+       int             len = 0;
 
        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,
+       len = kernel_sendpage(sock, headpage, headoffset,
                                  xdr->head[0].iov_len, flags);
        if (len != xdr->head[0].iov_len)
                goto out;
@@ -219,16 +198,58 @@ static int svc_sendto(struct svc_rqst *rqstp, struct xdr_buf *xdr)
                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);
-
+               result = kernel_sendpage(sock, tailpage, tailoffset,
+                                  xdr->tail[0].iov_len, 0);
                if (result > 0)
                        len += result;
        }
+
+out:
+       return len;
+}
+
+
+/*
+ * 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;
+       union {
+               struct cmsghdr  hdr;
+               long            all[SVC_PKTINFO_SPACE / sizeof(long)];
+       } buffer;
+       struct cmsghdr *cmh = &buffer.hdr;
+       int             len = 0;
+       unsigned long tailoff;
+       unsigned long headoff;
+       RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
+
+       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;
+       }
+
+       tailoff = ((unsigned long)xdr->tail[0].iov_base) & (PAGE_SIZE-1);
+       headoff = 0;
+       len = svc_send_common(sock, xdr, rqstp->rq_respages[0], headoff,
+                              rqstp->rq_respages[0], tailoff);
+
 out:
        dprintk("svc: socket %p sendto([%p %Zu... ], %d) = %d (addr %s)\n",
                svsk, xdr->head[0].iov_base, xdr->head[0].iov_len,
@@ -951,6 +972,57 @@ static int svc_tcp_recv_record(struct svc_sock *svsk, struct svc_rqst *rqstp)
        return -EAGAIN;
 }
 
+static int svc_process_calldir(struct svc_sock *svsk, struct svc_rqst *rqstp,
+                              struct rpc_rqst **reqpp, struct kvec *vec)
+{
+       struct rpc_rqst *req = NULL;
+       u32 *p;
+       u32 xid;
+       u32 calldir;
+       int len;
+
+       len = svc_recvfrom(rqstp, vec, 1, 8);
+       if (len < 0)
+               goto error;
+
+       p = (u32 *)rqstp->rq_arg.head[0].iov_base;
+       xid = *p++;
+       calldir = *p;
+
+       if (calldir == 0) {
+               /* REQUEST is the most common case */
+               vec[0] = rqstp->rq_arg.head[0];
+       } else {
+               /* REPLY */
+               if (svsk->sk_bc_xprt)
+                       req = xprt_lookup_rqst(svsk->sk_bc_xprt, xid);
+
+               if (!req) {
+                       printk(KERN_NOTICE
+                               "%s: Got unrecognized reply: "
+                               "calldir 0x%x sk_bc_xprt %p xid %08x\n",
+                               __func__, ntohl(calldir),
+                               svsk->sk_bc_xprt, xid);
+                       vec[0] = rqstp->rq_arg.head[0];
+                       goto out;
+               }
+
+               memcpy(&req->rq_private_buf, &req->rq_rcv_buf,
+                      sizeof(struct xdr_buf));
+               /* copy the xid and call direction */
+               memcpy(req->rq_private_buf.head[0].iov_base,
+                      rqstp->rq_arg.head[0].iov_base, 8);
+               vec[0] = req->rq_private_buf.head[0];
+       }
+ out:
+       vec[0].iov_base += 8;
+       vec[0].iov_len -= 8;
+       len = svsk->sk_reclen - 8;
+ error:
+       *reqpp = req;
+       return len;
+}
+
 /*
  * Receive data from a TCP socket.
  */
@@ -962,6 +1034,7 @@ static int svc_tcp_recvfrom(struct svc_rqst *rqstp)
        int             len;
        struct kvec *vec;
        int pnum, vlen;
+       struct rpc_rqst *req = NULL;
 
        dprintk("svc: tcp_recv %p data %d conn %d close %d\n",
                svsk, test_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags),
@@ -975,9 +1048,27 @@ static int svc_tcp_recvfrom(struct svc_rqst *rqstp)
        vec = rqstp->rq_vec;
        vec[0] = rqstp->rq_arg.head[0];
        vlen = PAGE_SIZE;
+
+       /*
+        * We have enough data for the whole tcp record. Let's try and read the
+        * first 8 bytes to get the xid and the call direction. We can use this
+        * to figure out if this is a call or a reply to a callback. If
+        * sk_reclen is < 8 (xid and calldir), then this is a malformed packet.
+        * In that case, don't bother with the calldir and just read the data.
+        * It will be rejected in svc_process.
+        */
+       if (len >= 8) {
+               len = svc_process_calldir(svsk, rqstp, &req, vec);
+               if (len < 0)
+                       goto err_again;
+               vlen -= 8;
+       }
+
        pnum = 1;
        while (vlen < len) {
-               vec[pnum].iov_base = page_address(rqstp->rq_pages[pnum]);
+               vec[pnum].iov_base = (req) ?
+                       page_address(req->rq_private_buf.pages[pnum - 1]) :
+                       page_address(rqstp->rq_pages[pnum]);
                vec[pnum].iov_len = PAGE_SIZE;
                pnum++;
                vlen += PAGE_SIZE;
@@ -989,6 +1080,16 @@ static int svc_tcp_recvfrom(struct svc_rqst *rqstp)
        if (len < 0)
                goto err_again;
 
+       /*
+        * Account for the 8 bytes we read earlier
+        */
+       len += 8;
+
+       if (req) {
+               xprt_complete_rqst(req->rq_task, len);
+               len = 0;
+               goto out;
+       }
        dprintk("svc: TCP complete record (%d bytes)\n", len);
        rqstp->rq_arg.len = len;
        rqstp->rq_arg.page_base = 0;
@@ -1002,6 +1103,7 @@ static int svc_tcp_recvfrom(struct svc_rqst *rqstp)
        rqstp->rq_xprt_ctxt   = NULL;
        rqstp->rq_prot        = IPPROTO_TCP;
 
+out:
        /* Reset TCP read info */
        svsk->sk_reclen = 0;
        svsk->sk_tcplen = 0;