From: NeilBrown Date: Tue, 6 Mar 2007 09:42:21 +0000 (-0800) Subject: [PATCH] knfsd: use recv_msg to get peer address for NFSD instead of code-copying X-Git-Tag: v2.6.21-rc3~28 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7a37f5787e76bf1765c1add3a9a7163f841a28bb;p=linux-2.6 [PATCH] knfsd: use recv_msg to get peer address for NFSD instead of code-copying The sunrpc server code needs to know the source and destination address for UDP packets so it can reply properly. It currently copies code out of the network stack to pick the pieces out of the skb. This is ugly and causes compile problems with the IPv6 stuff. So, rip that out and use recv_msg instead. This is a much cleaner interface, but has a slight cost in that the checksum is now checked before the copy, so we don't benefit from doing both at the same time. This can probably be fixed. Signed-off-by: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c index 63ae94771b..32b94cf19f 100644 --- a/net/sunrpc/svcsock.c +++ b/net/sunrpc/svcsock.c @@ -721,45 +721,23 @@ svc_write_space(struct sock *sk) } } -static void svc_udp_get_sender_address(struct svc_rqst *rqstp, - struct sk_buff *skb) +static inline void svc_udp_get_dest_address(struct svc_rqst *rqstp, + struct cmsghdr *cmh) { switch (rqstp->rq_sock->sk_sk->sk_family) { case AF_INET: { - /* this seems to come from net/ipv4/udp.c:udp_recvmsg */ - struct sockaddr_in *sin = svc_addr_in(rqstp); - - sin->sin_family = AF_INET; - sin->sin_port = skb->h.uh->source; - sin->sin_addr.s_addr = skb->nh.iph->saddr; - rqstp->rq_addrlen = sizeof(struct sockaddr_in); - /* Remember which interface received this request */ - rqstp->rq_daddr.addr.s_addr = skb->nh.iph->daddr; - } + struct in_pktinfo *pki = CMSG_DATA(cmh); + rqstp->rq_daddr.addr.s_addr = pki->ipi_spec_dst.s_addr; break; + } #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) case AF_INET6: { - /* this is derived from net/ipv6/udp.c:udpv6_recvmesg */ - struct sockaddr_in6 *sin6 = svc_addr_in6(rqstp); - - sin6->sin6_family = AF_INET6; - sin6->sin6_port = skb->h.uh->source; - sin6->sin6_flowinfo = 0; - sin6->sin6_scope_id = 0; - if (ipv6_addr_type(&sin6->sin6_addr) & - IPV6_ADDR_LINKLOCAL) - sin6->sin6_scope_id = IP6CB(skb)->iif; - ipv6_addr_copy(&sin6->sin6_addr, - &skb->nh.ipv6h->saddr); - rqstp->rq_addrlen = sizeof(struct sockaddr_in); - /* Remember which interface received this request */ - ipv6_addr_copy(&rqstp->rq_daddr.addr6, - &skb->nh.ipv6h->saddr); - } + struct in6_pktinfo *pki = CMSG_DATA(cmh); + ipv6_addr_copy(&rqstp->rq_daddr.addr6, &pki->ipi6_addr); break; + } #endif } - return; } /* @@ -771,7 +749,15 @@ svc_udp_recvfrom(struct svc_rqst *rqstp) struct svc_sock *svsk = rqstp->rq_sock; struct svc_serv *serv = svsk->sk_server; struct sk_buff *skb; + char buffer[CMSG_SPACE(sizeof(union svc_pktinfo_u))]; + struct cmsghdr *cmh = (struct cmsghdr *)buffer; 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(SK_CHNGBUF, &svsk->sk_flags)) /* udp sockets need large rcvbuf as all pending @@ -797,7 +783,9 @@ svc_udp_recvfrom(struct svc_rqst *rqstp) } clear_bit(SK_DATA, &svsk->sk_flags); - while ((skb = skb_recv_datagram(svsk->sk_sk, 0, 1, &err)) == NULL) { + while ((err == kernel_recvmsg(svsk->sk_sock, &msg, NULL, + 0, 0, MSG_PEEK | MSG_DONTWAIT)) < 0 || + (skb = skb_recv_datagram(svsk->sk_sk, 0, 1, &err)) == NULL) { if (err == -EAGAIN) { svc_sock_received(svsk); return err; @@ -805,6 +793,7 @@ svc_udp_recvfrom(struct svc_rqst *rqstp) /* possibly an icmp error */ dprintk("svc: recvfrom returned error %d\n", -err); } + rqstp->rq_addrlen = sizeof(rqstp->rq_addr); if (skb->tstamp.off_sec == 0) { struct timeval tv; @@ -827,7 +816,16 @@ svc_udp_recvfrom(struct svc_rqst *rqstp) rqstp->rq_prot = IPPROTO_UDP; - svc_udp_get_sender_address(rqstp, skb); + 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 */ @@ -884,6 +882,9 @@ svc_udp_sendto(struct svc_rqst *rqstp) static void svc_udp_init(struct svc_sock *svsk) { + int one = 1; + mm_segment_t oldfs; + svsk->sk_sk->sk_data_ready = svc_udp_data_ready; svsk->sk_sk->sk_write_space = svc_write_space; svsk->sk_recvfrom = svc_udp_recvfrom; @@ -899,6 +900,13 @@ svc_udp_init(struct svc_sock *svsk) set_bit(SK_DATA, &svsk->sk_flags); /* might have come in before data_ready set up */ set_bit(SK_CHNGBUF, &svsk->sk_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); } /*