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googlers / maze / linux / 3ca3c68e76686bee058937ade2b96f4de58ee434 / . / net / ipv4 / udp.c
blob: b63fd3d390244220e27e91997ce967aa1de8c209 [file] [log] [blame]
/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* The User Datagram Protocol (UDP).
*
* Version: $Id: udp.c,v 1.102 2002/02/01 22:01:04 davem Exp $
*
* Authors: Ross Biro
* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
* Arnt Gulbrandsen, <agulbra@nvg.unit.no>
* Alan Cox, <Alan.Cox@linux.org>
* Hirokazu Takahashi, <taka@valinux.co.jp>
*
* Fixes:
* Alan Cox : verify_area() calls
* Alan Cox : stopped close while in use off icmp
* messages. Not a fix but a botch that
* for udp at least is 'valid'.
* Alan Cox : Fixed icmp handling properly
* Alan Cox : Correct error for oversized datagrams
* Alan Cox : Tidied select() semantics.
* Alan Cox : udp_err() fixed properly, also now
* select and read wake correctly on errors
* Alan Cox : udp_send verify_area moved to avoid mem leak
* Alan Cox : UDP can count its memory
* Alan Cox : send to an unknown connection causes
* an ECONNREFUSED off the icmp, but
* does NOT close.
* Alan Cox : Switched to new sk_buff handlers. No more backlog!
* Alan Cox : Using generic datagram code. Even smaller and the PEEK
* bug no longer crashes it.
* Fred Van Kempen : Net2e support for sk->broadcast.
* Alan Cox : Uses skb_free_datagram
* Alan Cox : Added get/set sockopt support.
* Alan Cox : Broadcasting without option set returns EACCES.
* Alan Cox : No wakeup calls. Instead we now use the callbacks.
* Alan Cox : Use ip_tos and ip_ttl
* Alan Cox : SNMP Mibs
* Alan Cox : MSG_DONTROUTE, and 0.0.0.0 support.
* Matt Dillon : UDP length checks.
* Alan Cox : Smarter af_inet used properly.
* Alan Cox : Use new kernel side addressing.
* Alan Cox : Incorrect return on truncated datagram receive.
* Arnt Gulbrandsen : New udp_send and stuff
* Alan Cox : Cache last socket
* Alan Cox : Route cache
* Jon Peatfield : Minor efficiency fix to sendto().
* Mike Shaver : RFC1122 checks.
* Alan Cox : Nonblocking error fix.
* Willy Konynenberg : Transparent proxying support.
* Mike McLagan : Routing by source
* David S. Miller : New socket lookup architecture.
* Last socket cache retained as it
* does have a high hit rate.
* Olaf Kirch : Don't linearise iovec on sendmsg.
* Andi Kleen : Some cleanups, cache destination entry
* for connect.
* Vitaly E. Lavrov : Transparent proxy revived after year coma.
* Melvin Smith : Check msg_name not msg_namelen in sendto(),
* return ENOTCONN for unconnected sockets (POSIX)
* Janos Farkas : don't deliver multi/broadcasts to a different
* bound-to-device socket
* Hirokazu Takahashi : HW checksumming for outgoing UDP
* datagrams.
* Hirokazu Takahashi : sendfile() on UDP works now.
* Arnaldo C. Melo : convert /proc/net/udp to seq_file
* YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
* Alexey Kuznetsov: allow both IPv4 and IPv6 sockets to bind
* a single port at the same time.
* Derek Atkins <derek@ihtfp.com>: Add Encapulation Support
*
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/ioctls.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/module.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/igmp.h>
#include <linux/in.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/inet.h>
#include <linux/ipv6.h>
#include <linux/netdevice.h>
#include <net/snmp.h>
#include <net/ip.h>
#include <net/tcp_states.h>
#include <net/protocol.h>
#include <linux/skbuff.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <net/sock.h>
#include <net/udp.h>
#include <net/icmp.h>
#include <net/route.h>
#include <net/inet_common.h>
#include <net/checksum.h>
#include <net/xfrm.h>
/*
* Snmp MIB for the UDP layer
*/
DEFINE_SNMP_STAT(struct udp_mib, udp_statistics) __read_mostly;
struct hlist_head udp_hash[UDP_HTABLE_SIZE];
DEFINE_RWLOCK(udp_hash_lock);
static int udp_port_rover;
static inline int udp_lport_inuse(u16 num)
{
struct sock *sk;
struct hlist_node *node;
sk_for_each(sk, node, &udp_hash[num & (UDP_HTABLE_SIZE - 1)])
if (inet_sk(sk)->num == num)
return 1;
return 0;
}
/**
* udp_get_port - common port lookup for IPv4 and IPv6
*
* @sk: socket struct in question
* @snum: port number to look up
* @saddr_comp: AF-dependent comparison of bound local IP addresses
*/
int udp_get_port(struct sock *sk, unsigned short snum,
int (*saddr_cmp)(const struct sock *sk1, const struct sock *sk2))
{
struct hlist_node *node;
struct hlist_head *head;
struct sock *sk2;
int error = 1;
write_lock_bh(&udp_hash_lock);
if (snum == 0) {
int best_size_so_far, best, result, i;
if (udp_port_rover > sysctl_local_port_range[1] ||
udp_port_rover < sysctl_local_port_range[0])
udp_port_rover = sysctl_local_port_range[0];
best_size_so_far = 32767;
best = result = udp_port_rover;
for (i = 0; i < UDP_HTABLE_SIZE; i++, result++) {
int size;
head = &udp_hash[result & (UDP_HTABLE_SIZE - 1)];
if (hlist_empty(head)) {
if (result > sysctl_local_port_range[1])
result = sysctl_local_port_range[0] +
((result - sysctl_local_port_range[0]) &
(UDP_HTABLE_SIZE - 1));
goto gotit;
}
size = 0;
sk_for_each(sk2, node, head)
if (++size < best_size_so_far) {
best_size_so_far = size;
best = result;
}
}
result = best;
for(i = 0; i < (1 << 16) / UDP_HTABLE_SIZE; i++, result += UDP_HTABLE_SIZE) {
if (result > sysctl_local_port_range[1])
result = sysctl_local_port_range[0]
+ ((result - sysctl_local_port_range[0]) &
(UDP_HTABLE_SIZE - 1));
if (!udp_lport_inuse(result))
break;
}
if (i >= (1 << 16) / UDP_HTABLE_SIZE)
goto fail;
gotit:
udp_port_rover = snum = result;
} else {
head = &udp_hash[snum & (UDP_HTABLE_SIZE - 1)];
sk_for_each(sk2, node, head)
if (inet_sk(sk2)->num == snum &&
sk2 != sk &&
(!sk2->sk_reuse || !sk->sk_reuse) &&
(!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if
|| sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
(*saddr_cmp)(sk, sk2) )
goto fail;
}
inet_sk(sk)->num = snum;
if (sk_unhashed(sk)) {
head = &udp_hash[snum & (UDP_HTABLE_SIZE - 1)];
sk_add_node(sk, head);
sock_prot_inc_use(sk->sk_prot);
}
error = 0;
fail:
write_unlock_bh(&udp_hash_lock);
return error;
}
static inline int ipv4_rcv_saddr_equal(const struct sock *sk1, const struct sock *sk2)
{
struct inet_sock *inet1 = inet_sk(sk1), *inet2 = inet_sk(sk2);
return ( !ipv6_only_sock(sk2) &&
(!inet1->rcv_saddr || !inet2->rcv_saddr ||
inet1->rcv_saddr == inet2->rcv_saddr ));
}
static inline int udp_v4_get_port(struct sock *sk, unsigned short snum)
{
return udp_get_port(sk, snum, ipv4_rcv_saddr_equal);
}
static void udp_v4_hash(struct sock *sk)
{
BUG();
}
static void udp_v4_unhash(struct sock *sk)
{
write_lock_bh(&udp_hash_lock);
if (sk_del_node_init(sk)) {
inet_sk(sk)->num = 0;
sock_prot_dec_use(sk->sk_prot);
}
write_unlock_bh(&udp_hash_lock);
}
/* UDP is nearly always wildcards out the wazoo, it makes no sense to try
* harder than this. -DaveM
*/
static struct sock *udp_v4_lookup_longway(u32 saddr, u16 sport,
u32 daddr, u16 dport, int dif)
{
struct sock *sk, *result = NULL;
struct hlist_node *node;
unsigned short hnum = ntohs(dport);
int badness = -1;
sk_for_each(sk, node, &udp_hash[hnum & (UDP_HTABLE_SIZE - 1)]) {
struct inet_sock *inet = inet_sk(sk);
if (inet->num == hnum && !ipv6_only_sock(sk)) {
int score = (sk->sk_family == PF_INET ? 1 : 0);
if (inet->rcv_saddr) {
if (inet->rcv_saddr != daddr)
continue;
score+=2;
}
if (inet->daddr) {
if (inet->daddr != saddr)
continue;
score+=2;
}
if (inet->dport) {
if (inet->dport != sport)
continue;
score+=2;
}
if (sk->sk_bound_dev_if) {
if (sk->sk_bound_dev_if != dif)
continue;
score+=2;
}
if(score == 9) {
result = sk;
break;
} else if(score > badness) {
result = sk;
badness = score;
}
}
}
return result;
}
static __inline__ struct sock *udp_v4_lookup(u32 saddr, u16 sport,
u32 daddr, u16 dport, int dif)
{
struct sock *sk;
read_lock(&udp_hash_lock);
sk = udp_v4_lookup_longway(saddr, sport, daddr, dport, dif);
if (sk)
sock_hold(sk);
read_unlock(&udp_hash_lock);
return sk;
}
static inline struct sock *udp_v4_mcast_next(struct sock *sk,
u16 loc_port, u32 loc_addr,
u16 rmt_port, u32 rmt_addr,
int dif)
{
struct hlist_node *node;
struct sock *s = sk;
unsigned short hnum = ntohs(loc_port);
sk_for_each_from(s, node) {
struct inet_sock *inet = inet_sk(s);
if (inet->num != hnum ||
(inet->daddr && inet->daddr != rmt_addr) ||
(inet->dport != rmt_port && inet->dport) ||
(inet->rcv_saddr && inet->rcv_saddr != loc_addr) ||
ipv6_only_sock(s) ||
(s->sk_bound_dev_if && s->sk_bound_dev_if != dif))
continue;
if (!ip_mc_sf_allow(s, loc_addr, rmt_addr, dif))
continue;
goto found;
}
s = NULL;
found:
return s;
}
/*
* This routine is called by the ICMP module when it gets some
* sort of error condition. If err < 0 then the socket should
* be closed and the error returned to the user. If err > 0
* it's just the icmp type << 8 | icmp code.
* Header points to the ip header of the error packet. We move
* on past this. Then (as it used to claim before adjustment)
* header points to the first 8 bytes of the udp header. We need
* to find the appropriate port.
*/
void udp_err(struct sk_buff *skb, u32 info)
{
struct inet_sock *inet;
struct iphdr *iph = (struct iphdr*)skb->data;
struct udphdr *uh = (struct udphdr*)(skb->data+(iph->ihl<<2));
int type = skb->h.icmph->type;
int code = skb->h.icmph->code;
struct sock *sk;
int harderr;
int err;
sk = udp_v4_lookup(iph->daddr, uh->dest, iph->saddr, uh->source, skb->dev->ifindex);
if (sk == NULL) {
ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
return; /* No socket for error */
}
err = 0;
harderr = 0;
inet = inet_sk(sk);
switch (type) {
default:
case ICMP_TIME_EXCEEDED:
err = EHOSTUNREACH;
break;
case ICMP_SOURCE_QUENCH:
goto out;
case ICMP_PARAMETERPROB:
err = EPROTO;
harderr = 1;
break;
case ICMP_DEST_UNREACH:
if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
if (inet->pmtudisc != IP_PMTUDISC_DONT) {
err = EMSGSIZE;
harderr = 1;
break;
}
goto out;
}
err = EHOSTUNREACH;
if (code <= NR_ICMP_UNREACH) {
harderr = icmp_err_convert[code].fatal;
err = icmp_err_convert[code].errno;
}
break;
}
/*
* RFC1122: OK. Passes ICMP errors back to application, as per
* 4.1.3.3.
*/
if (!inet->recverr) {
if (!harderr || sk->sk_state != TCP_ESTABLISHED)
goto out;
} else {
ip_icmp_error(sk, skb, err, uh->dest, info, (u8*)(uh+1));
}
sk->sk_err = err;
sk->sk_error_report(sk);
out:
sock_put(sk);
}
/*
* Throw away all pending data and cancel the corking. Socket is locked.
*/
static void udp_flush_pending_frames(struct sock *sk)
{
struct udp_sock *up = udp_sk(sk);
if (up->pending) {
up->len = 0;
up->pending = 0;
ip_flush_pending_frames(sk);
}
}
/*
* Push out all pending data as one UDP datagram. Socket is locked.
*/
static int udp_push_pending_frames(struct sock *sk, struct udp_sock *up)
{
struct inet_sock *inet = inet_sk(sk);
struct flowi *fl = &inet->cork.fl;
struct sk_buff *skb;
struct udphdr *uh;
int err = 0;
/* Grab the skbuff where UDP header space exists. */
if ((skb = skb_peek(&sk->sk_write_queue)) == NULL)
goto out;
/*
* Create a UDP header
*/
uh = skb->h.uh;
uh->source = fl->fl_ip_sport;
uh->dest = fl->fl_ip_dport;
uh->len = htons(up->len);
uh->check = 0;
if (sk->sk_no_check == UDP_CSUM_NOXMIT) {
skb->ip_summed = CHECKSUM_NONE;
goto send;
}
if (skb_queue_len(&sk->sk_write_queue) == 1) {
/*
* Only one fragment on the socket.
*/
if (skb->ip_summed == CHECKSUM_PARTIAL) {
skb->csum = offsetof(struct udphdr, check);
uh->check = ~csum_tcpudp_magic(fl->fl4_src, fl->fl4_dst,
up->len, IPPROTO_UDP, 0);
} else {
skb->csum = csum_partial((char *)uh,
sizeof(struct udphdr), skb->csum);
uh->check = csum_tcpudp_magic(fl->fl4_src, fl->fl4_dst,
up->len, IPPROTO_UDP, skb->csum);
if (uh->check == 0)
uh->check = -1;
}
} else {
unsigned int csum = 0;
/*
* HW-checksum won't work as there are two or more
* fragments on the socket so that all csums of sk_buffs
* should be together.
*/
if (skb->ip_summed == CHECKSUM_PARTIAL) {
int offset = (unsigned char *)uh - skb->data;
skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
skb->ip_summed = CHECKSUM_NONE;
} else {
skb->csum = csum_partial((char *)uh,
sizeof(struct udphdr), skb->csum);
}
skb_queue_walk(&sk->sk_write_queue, skb) {
csum = csum_add(csum, skb->csum);
}
uh->check = csum_tcpudp_magic(fl->fl4_src, fl->fl4_dst,
up->len, IPPROTO_UDP, csum);
if (uh->check == 0)
uh->check = -1;
}
send:
err = ip_push_pending_frames(sk);
out:
up->len = 0;
up->pending = 0;
return err;
}
static unsigned short udp_check(struct udphdr *uh, int len, unsigned long saddr, unsigned long daddr, unsigned long base)
{
return(csum_tcpudp_magic(saddr, daddr, len, IPPROTO_UDP, base));
}
int udp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
size_t len)
{
struct inet_sock *inet = inet_sk(sk);
struct udp_sock *up = udp_sk(sk);
int ulen = len;
struct ipcm_cookie ipc;
struct rtable *rt = NULL;
int free = 0;
int connected = 0;
__be32 daddr, faddr, saddr;
u16 dport;
u8 tos;
int err;
int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
if (len > 0xFFFF)
return -EMSGSIZE;
/*
* Check the flags.
*/
if (msg->msg_flags&MSG_OOB) /* Mirror BSD error message compatibility */
return -EOPNOTSUPP;
ipc.opt = NULL;
if (up->pending) {
/*
* There are pending frames.
* The socket lock must be held while it's corked.
*/
lock_sock(sk);
if (likely(up->pending)) {
if (unlikely(up->pending != AF_INET)) {
release_sock(sk);
return -EINVAL;
}
goto do_append_data;
}
release_sock(sk);
}
ulen += sizeof(struct udphdr);
/*
* Get and verify the address.
*/
if (msg->msg_name) {
struct sockaddr_in * usin = (struct sockaddr_in*)msg->msg_name;
if (msg->msg_namelen < sizeof(*usin))
return -EINVAL;
if (usin->sin_family != AF_INET) {
if (usin->sin_family != AF_UNSPEC)
return -EAFNOSUPPORT;
}
daddr = usin->sin_addr.s_addr;
dport = usin->sin_port;
if (dport == 0)
return -EINVAL;
} else {
if (sk->sk_state != TCP_ESTABLISHED)
return -EDESTADDRREQ;
daddr = inet->daddr;
dport = inet->dport;
/* Open fast path for connected socket.
Route will not be used, if at least one option is set.
*/
connected = 1;
}
ipc.addr = inet->saddr;
ipc.oif = sk->sk_bound_dev_if;
if (msg->msg_controllen) {
err = ip_cmsg_send(msg, &ipc);
if (err)
return err;
if (ipc.opt)
free = 1;
connected = 0;
}
if (!ipc.opt)
ipc.opt = inet->opt;
saddr = ipc.addr;
ipc.addr = faddr = daddr;
if (ipc.opt && ipc.opt->srr) {
if (!daddr)
return -EINVAL;
faddr = ipc.opt->faddr;
connected = 0;
}
tos = RT_TOS(inet->tos);
if (sock_flag(sk, SOCK_LOCALROUTE) ||
(msg->msg_flags & MSG_DONTROUTE) ||
(ipc.opt && ipc.opt->is_strictroute)) {
tos |= RTO_ONLINK;
connected = 0;
}
if (MULTICAST(daddr)) {
if (!ipc.oif)
ipc.oif = inet->mc_index;
if (!saddr)
saddr = inet->mc_addr;
connected = 0;
}
if (connected)
rt = (struct rtable*)sk_dst_check(sk, 0);
if (rt == NULL) {
struct flowi fl = { .oif = ipc.oif,
.nl_u = { .ip4_u =
{ .daddr = faddr,
.saddr = saddr,
.tos = tos } },
.proto = IPPROTO_UDP,
.uli_u = { .ports =
{ .sport = inet->sport,
.dport = dport } } };
security_sk_classify_flow(sk, &fl);
err = ip_route_output_flow(&rt, &fl, sk, !(msg->msg_flags&MSG_DONTWAIT));
if (err)
goto out;
err = -EACCES;
if ((rt->rt_flags & RTCF_BROADCAST) &&
!sock_flag(sk, SOCK_BROADCAST))
goto out;
if (connected)
sk_dst_set(sk, dst_clone(&rt->u.dst));
}
if (msg->msg_flags&MSG_CONFIRM)
goto do_confirm;
back_from_confirm:
saddr = rt->rt_src;
if (!ipc.addr)
daddr = ipc.addr = rt->rt_dst;
lock_sock(sk);
if (unlikely(up->pending)) {
/* The socket is already corked while preparing it. */
/* ... which is an evident application bug. --ANK */
release_sock(sk);
LIMIT_NETDEBUG(KERN_DEBUG "udp cork app bug 2\n");
err = -EINVAL;
goto out;
}
/*
* Now cork the socket to pend data.
*/
inet->cork.fl.fl4_dst = daddr;
inet->cork.fl.fl_ip_dport = dport;
inet->cork.fl.fl4_src = saddr;
inet->cork.fl.fl_ip_sport = inet->sport;
up->pending = AF_INET;
do_append_data:
up->len += ulen;
err = ip_append_data(sk, ip_generic_getfrag, msg->msg_iov, ulen,
sizeof(struct udphdr), &ipc, rt,
corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
if (err)
udp_flush_pending_frames(sk);
else if (!corkreq)
err = udp_push_pending_frames(sk, up);
release_sock(sk);
out:
ip_rt_put(rt);
if (free)
kfree(ipc.opt);
if (!err) {
UDP_INC_STATS_USER(UDP_MIB_OUTDATAGRAMS);
return len;
}
/*
* ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space. Reporting
* ENOBUFS might not be good (it's not tunable per se), but otherwise
* we don't have a good statistic (IpOutDiscards but it can be too many
* things). We could add another new stat but at least for now that
* seems like overkill.
*/
if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
UDP_INC_STATS_USER(UDP_MIB_SNDBUFERRORS);
}
return err;
do_confirm:
dst_confirm(&rt->u.dst);
if (!(msg->msg_flags&MSG_PROBE) || len)
goto back_from_confirm;
err = 0;
goto out;
}
static int udp_sendpage(struct sock *sk, struct page *page, int offset,
size_t size, int flags)
{
struct udp_sock *up = udp_sk(sk);
int ret;
if (!up->pending) {
struct msghdr msg = { .msg_flags = flags|MSG_MORE };
/* Call udp_sendmsg to specify destination address which
* sendpage interface can't pass.
* This will succeed only when the socket is connected.
*/
ret = udp_sendmsg(NULL, sk, &msg, 0);
if (ret < 0)
return ret;
}
lock_sock(sk);
if (unlikely(!up->pending)) {
release_sock(sk);
LIMIT_NETDEBUG(KERN_DEBUG "udp cork app bug 3\n");
return -EINVAL;
}
ret = ip_append_page(sk, page, offset, size, flags);
if (ret == -EOPNOTSUPP) {
release_sock(sk);
return sock_no_sendpage(sk->sk_socket, page, offset,
size, flags);
}
if (ret < 0) {
udp_flush_pending_frames(sk);
goto out;
}
up->len += size;
if (!(up->corkflag || (flags&MSG_MORE)))
ret = udp_push_pending_frames(sk, up);
if (!ret)
ret = size;
out:
release_sock(sk);
return ret;
}
/*
* IOCTL requests applicable to the UDP protocol
*/
int udp_ioctl(struct sock *sk, int cmd, unsigned long arg)
{
switch(cmd)
{
case SIOCOUTQ:
{
int amount = atomic_read(&sk->sk_wmem_alloc);
return put_user(amount, (int __user *)arg);
}
case SIOCINQ:
{
struct sk_buff *skb;
unsigned long amount;
amount = 0;
spin_lock_bh(&sk->sk_receive_queue.lock);
skb = skb_peek(&sk->sk_receive_queue);
if (skb != NULL) {
/*
* We will only return the amount
* of this packet since that is all
* that will be read.
*/
amount = skb->len - sizeof(struct udphdr);
}
spin_unlock_bh(&sk->sk_receive_queue.lock);
return put_user(amount, (int __user *)arg);
}
default:
return -ENOIOCTLCMD;
}
return(0);
}
static __inline__ int __udp_checksum_complete(struct sk_buff *skb)
{
return __skb_checksum_complete(skb);
}
static __inline__ int udp_checksum_complete(struct sk_buff *skb)
{
return skb->ip_summed != CHECKSUM_UNNECESSARY &&
__udp_checksum_complete(skb);
}
/*
* This should be easy, if there is something there we
* return it, otherwise we block.
*/
static int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
size_t len, int noblock, int flags, int *addr_len)
{
struct inet_sock *inet = inet_sk(sk);
struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
struct sk_buff *skb;
int copied, err;
/*
* Check any passed addresses
*/
if (addr_len)
*addr_len=sizeof(*sin);
if (flags & MSG_ERRQUEUE)
return ip_recv_error(sk, msg, len);
try_again:
skb = skb_recv_datagram(sk, flags, noblock, &err);
if (!skb)
goto out;
copied = skb->len - sizeof(struct udphdr);
if (copied > len) {
copied = len;
msg->msg_flags |= MSG_TRUNC;
}
if (skb->ip_summed==CHECKSUM_UNNECESSARY) {
err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr), msg->msg_iov,
copied);
} else if (msg->msg_flags&MSG_TRUNC) {
if (__udp_checksum_complete(skb))
goto csum_copy_err;
err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr), msg->msg_iov,
copied);
} else {
err = skb_copy_and_csum_datagram_iovec(skb, sizeof(struct udphdr), msg->msg_iov);
if (err == -EINVAL)
goto csum_copy_err;
}
if (err)
goto out_free;
sock_recv_timestamp(msg, sk, skb);
/* Copy the address. */
if (sin)
{
sin->sin_family = AF_INET;
sin->sin_port = skb->h.uh->source;
sin->sin_addr.s_addr = skb->nh.iph->saddr;
memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
}
if (inet->cmsg_flags)
ip_cmsg_recv(msg, skb);
err = copied;
if (flags & MSG_TRUNC)
err = skb->len - sizeof(struct udphdr);
out_free:
skb_free_datagram(sk, skb);
out:
return err;
csum_copy_err:
UDP_INC_STATS_BH(UDP_MIB_INERRORS);
skb_kill_datagram(sk, skb, flags);
if (noblock)
return -EAGAIN;
goto try_again;
}
int udp_disconnect(struct sock *sk, int flags)
{
struct inet_sock *inet = inet_sk(sk);
/*
* 1003.1g - break association.
*/
sk->sk_state = TCP_CLOSE;
inet->daddr = 0;
inet->dport = 0;
sk->sk_bound_dev_if = 0;
if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
inet_reset_saddr(sk);
if (!(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) {
sk->sk_prot->unhash(sk);
inet->sport = 0;
}
sk_dst_reset(sk);
return 0;
}
static void udp_close(struct sock *sk, long timeout)
{
sk_common_release(sk);
}
/* return:
* 1 if the the UDP system should process it
* 0 if we should drop this packet
* -1 if it should get processed by xfrm4_rcv_encap
*/
static int udp_encap_rcv(struct sock * sk, struct sk_buff *skb)
{
#ifndef CONFIG_XFRM
return 1;
#else
struct udp_sock *up = udp_sk(sk);
struct udphdr *uh = skb->h.uh;
struct iphdr *iph;
int iphlen, len;
__u8 *udpdata = (__u8 *)uh + sizeof(struct udphdr);
__u32 *udpdata32 = (__u32 *)udpdata;
__u16 encap_type = up->encap_type;
/* if we're overly short, let UDP handle it */
if (udpdata > skb->tail)
return 1;
/* if this is not encapsulated socket, then just return now */
if (!encap_type)
return 1;
len = skb->tail - udpdata;
switch (encap_type) {
default:
case UDP_ENCAP_ESPINUDP:
/* Check if this is a keepalive packet. If so, eat it. */
if (len == 1 && udpdata[0] == 0xff) {
return 0;
} else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0 ) {
/* ESP Packet without Non-ESP header */
len = sizeof(struct udphdr);
} else
/* Must be an IKE packet.. pass it through */
return 1;
break;
case UDP_ENCAP_ESPINUDP_NON_IKE:
/* Check if this is a keepalive packet. If so, eat it. */
if (len == 1 && udpdata[0] == 0xff) {
return 0;
} else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) &&
udpdata32[0] == 0 && udpdata32[1] == 0) {
/* ESP Packet with Non-IKE marker */
len = sizeof(struct udphdr) + 2 * sizeof(u32);
} else
/* Must be an IKE packet.. pass it through */
return 1;
break;
}
/* At this point we are sure that this is an ESPinUDP packet,
* so we need to remove 'len' bytes from the packet (the UDP
* header and optional ESP marker bytes) and then modify the
* protocol to ESP, and then call into the transform receiver.
*/
if (skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
return 0;
/* Now we can update and verify the packet length... */
iph = skb->nh.iph;
iphlen = iph->ihl << 2;
iph->tot_len = htons(ntohs(iph->tot_len) - len);
if (skb->len < iphlen + len) {
/* packet is too small!?! */
return 0;
}
/* pull the data buffer up to the ESP header and set the
* transport header to point to ESP. Keep UDP on the stack
* for later.
*/
skb->h.raw = skb_pull(skb, len);
/* modify the protocol (it's ESP!) */
iph->protocol = IPPROTO_ESP;
/* and let the caller know to send this into the ESP processor... */
return -1;
#endif
}
/* returns:
* -1: error
* 0: success
* >0: "udp encap" protocol resubmission
*
* Note that in the success and error cases, the skb is assumed to
* have either been requeued or freed.
*/
static int udp_queue_rcv_skb(struct sock * sk, struct sk_buff *skb)
{
struct udp_sock *up = udp_sk(sk);
int rc;
/*
* Charge it to the socket, dropping if the queue is full.
*/
if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) {
kfree_skb(skb);
return -1;
}
nf_reset(skb);
if (up->encap_type) {
/*
* This is an encapsulation socket, so let's see if this is
* an encapsulated packet.
* If it's a keepalive packet, then just eat it.
* If it's an encapsulateed packet, then pass it to the
* IPsec xfrm input and return the response
* appropriately. Otherwise, just fall through and
* pass this up the UDP socket.
*/
int ret;
ret = udp_encap_rcv(sk, skb);
if (ret == 0) {
/* Eat the packet .. */
kfree_skb(skb);
return 0;
}
if (ret < 0) {
/* process the ESP packet */
ret = xfrm4_rcv_encap(skb, up->encap_type);
UDP_INC_STATS_BH(UDP_MIB_INDATAGRAMS);
return -ret;
}
/* FALLTHROUGH -- it's a UDP Packet */
}
if (sk->sk_filter && skb->ip_summed != CHECKSUM_UNNECESSARY) {
if (__udp_checksum_complete(skb)) {
UDP_INC_STATS_BH(UDP_MIB_INERRORS);
kfree_skb(skb);
return -1;
}
skb->ip_summed = CHECKSUM_UNNECESSARY;
}
if ((rc = sock_queue_rcv_skb(sk,skb)) < 0) {
/* Note that an ENOMEM error is charged twice */
if (rc == -ENOMEM)
UDP_INC_STATS_BH(UDP_MIB_RCVBUFERRORS);
UDP_INC_STATS_BH(UDP_MIB_INERRORS);
kfree_skb(skb);
return -1;
}
UDP_INC_STATS_BH(UDP_MIB_INDATAGRAMS);
return 0;
}
/*
* Multicasts and broadcasts go to each listener.
*
* Note: called only from the BH handler context,
* so we don't need to lock the hashes.
*/
static int udp_v4_mcast_deliver(struct sk_buff *skb, struct udphdr *uh,
u32 saddr, u32 daddr)
{
struct sock *sk;
int dif;
read_lock(&udp_hash_lock);
sk = sk_head(&udp_hash[ntohs(uh->dest) & (UDP_HTABLE_SIZE - 1)]);
dif = skb->dev->ifindex;
sk = udp_v4_mcast_next(sk, uh->dest, daddr, uh->source, saddr, dif);
if (sk) {
struct sock *sknext = NULL;
do {
struct sk_buff *skb1 = skb;
sknext = udp_v4_mcast_next(sk_next(sk), uh->dest, daddr,
uh->source, saddr, dif);
if(sknext)
skb1 = skb_clone(skb, GFP_ATOMIC);
if(skb1) {
int ret = udp_queue_rcv_skb(sk, skb1);
if (ret > 0)
/* we should probably re-process instead
* of dropping packets here. */
kfree_skb(skb1);
}
sk = sknext;
} while(sknext);
} else
kfree_skb(skb);
read_unlock(&udp_hash_lock);
return 0;
}
/* Initialize UDP checksum. If exited with zero value (success),
* CHECKSUM_UNNECESSARY means, that no more checks are required.
* Otherwise, csum completion requires chacksumming packet body,
* including udp header and folding it to skb->csum.
*/
static void udp_checksum_init(struct sk_buff *skb, struct udphdr *uh,
unsigned short ulen, u32 saddr, u32 daddr)
{
if (uh->check == 0) {
skb->ip_summed = CHECKSUM_UNNECESSARY;
} else if (skb->ip_summed == CHECKSUM_COMPLETE) {
if (!udp_check(uh, ulen, saddr, daddr, skb->csum))
skb->ip_summed = CHECKSUM_UNNECESSARY;
}
if (skb->ip_summed != CHECKSUM_UNNECESSARY)
skb->csum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
/* Probably, we should checksum udp header (it should be in cache
* in any case) and data in tiny packets (< rx copybreak).
*/
}
/*
* All we need to do is get the socket, and then do a checksum.
*/
int udp_rcv(struct sk_buff *skb)
{
struct sock *sk;
struct udphdr *uh;
unsigned short ulen;
struct rtable *rt = (struct rtable*)skb->dst;
u32 saddr = skb->nh.iph->saddr;
u32 daddr = skb->nh.iph->daddr;
int len = skb->len;
/*
* Validate the packet and the UDP length.
*/
if (!pskb_may_pull(skb, sizeof(struct udphdr)))
goto no_header;
uh = skb->h.uh;
ulen = ntohs(uh->len);
if (ulen > len || ulen < sizeof(*uh))
goto short_packet;
if (pskb_trim_rcsum(skb, ulen))
goto short_packet;
udp_checksum_init(skb, uh, ulen, saddr, daddr);
if(rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST))
return udp_v4_mcast_deliver(skb, uh, saddr, daddr);
sk = udp_v4_lookup(saddr, uh->source, daddr, uh->dest, skb->dev->ifindex);
if (sk != NULL) {
int ret = udp_queue_rcv_skb(sk, skb);
sock_put(sk);
/* a return value > 0 means to resubmit the input, but
* it it wants the return to be -protocol, or 0
*/
if (ret > 0)
return -ret;
return 0;
}
if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
goto drop;
nf_reset(skb);
/* No socket. Drop packet silently, if checksum is wrong */
if (udp_checksum_complete(skb))
goto csum_error;
UDP_INC_STATS_BH(UDP_MIB_NOPORTS);
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
/*
* Hmm. We got an UDP packet to a port to which we
* don't wanna listen. Ignore it.
*/
kfree_skb(skb);
return(0);
short_packet:
LIMIT_NETDEBUG(KERN_DEBUG "UDP: short packet: From %u.%u.%u.%u:%u %d/%d to %u.%u.%u.%u:%u\n",
NIPQUAD(saddr),
ntohs(uh->source),
ulen,
len,
NIPQUAD(daddr),
ntohs(uh->dest));
no_header:
UDP_INC_STATS_BH(UDP_MIB_INERRORS);
kfree_skb(skb);
return(0);
csum_error:
/*
* RFC1122: OK. Discards the bad packet silently (as far as
* the network is concerned, anyway) as per 4.1.3.4 (MUST).
*/
LIMIT_NETDEBUG(KERN_DEBUG "UDP: bad checksum. From %d.%d.%d.%d:%d to %d.%d.%d.%d:%d ulen %d\n",
NIPQUAD(saddr),
ntohs(uh->source),
NIPQUAD(daddr),
ntohs(uh->dest),
ulen);
drop:
UDP_INC_STATS_BH(UDP_MIB_INERRORS);
kfree_skb(skb);
return(0);
}
static int udp_destroy_sock(struct sock *sk)
{
lock_sock(sk);
udp_flush_pending_frames(sk);
release_sock(sk);
return 0;
}
/*
* Socket option code for UDP
*/
static int do_udp_setsockopt(struct sock *sk, int level, int optname,
char __user *optval, int optlen)
{
struct udp_sock *up = udp_sk(sk);
int val;
int err = 0;
if(optlen<sizeof(int))
return -EINVAL;
if (get_user(val, (int __user *)optval))
return -EFAULT;
switch(optname) {
case UDP_CORK:
if (val != 0) {
up->corkflag = 1;
} else {
up->corkflag = 0;
lock_sock(sk);
udp_push_pending_frames(sk, up);
release_sock(sk);
}
break;
case UDP_ENCAP:
switch (val) {
case 0:
case UDP_ENCAP_ESPINUDP:
case UDP_ENCAP_ESPINUDP_NON_IKE:
up->encap_type = val;
break;
default:
err = -ENOPROTOOPT;
break;
}
break;
default:
err = -ENOPROTOOPT;
break;
};
return err;
}
static int udp_setsockopt(struct sock *sk, int level, int optname,
char __user *optval, int optlen)
{
if (level != SOL_UDP)
return ip_setsockopt(sk, level, optname, optval, optlen);
return do_udp_setsockopt(sk, level, optname, optval, optlen);
}
#ifdef CONFIG_COMPAT
static int compat_udp_setsockopt(struct sock *sk, int level, int optname,
char __user *optval, int optlen)
{
if (level != SOL_UDP)
return compat_ip_setsockopt(sk, level, optname, optval, optlen);
return do_udp_setsockopt(sk, level, optname, optval, optlen);
}
#endif
static int do_udp_getsockopt(struct sock *sk, int level, int optname,
char __user *optval, int __user *optlen)
{
struct udp_sock *up = udp_sk(sk);
int val, len;
if(get_user(len,optlen))
return -EFAULT;
len = min_t(unsigned int, len, sizeof(int));
if(len < 0)
return -EINVAL;
switch(optname) {
case UDP_CORK:
val = up->corkflag;
break;
case UDP_ENCAP:
val = up->encap_type;
break;
default:
return -ENOPROTOOPT;
};
if(put_user(len, optlen))
return -EFAULT;
if(copy_to_user(optval, &val,len))
return -EFAULT;
return 0;
}
static int udp_getsockopt(struct sock *sk, int level, int optname,
char __user *optval, int __user *optlen)
{
if (level != SOL_UDP)
return ip_getsockopt(sk, level, optname, optval, optlen);
return do_udp_getsockopt(sk, level, optname, optval, optlen);
}
#ifdef CONFIG_COMPAT
static int compat_udp_getsockopt(struct sock *sk, int level, int optname,
char __user *optval, int __user *optlen)
{
if (level != SOL_UDP)
return compat_ip_getsockopt(sk, level, optname, optval, optlen);
return do_udp_getsockopt(sk, level, optname, optval, optlen);
}
#endif
/**
* udp_poll - wait for a UDP event.
* @file - file struct
* @sock - socket
* @wait - poll table
*
* This is same as datagram poll, except for the special case of
* blocking sockets. If application is using a blocking fd
* and a packet with checksum error is in the queue;
* then it could get return from select indicating data available
* but then block when reading it. Add special case code
* to work around these arguably broken applications.
*/
unsigned int udp_poll(struct file *file, struct socket *sock, poll_table *wait)
{
unsigned int mask = datagram_poll(file, sock, wait);
struct sock *sk = sock->sk;
/* Check for false positives due to checksum errors */
if ( (mask & POLLRDNORM) &&
!(file->f_flags & O_NONBLOCK) &&
!(sk->sk_shutdown & RCV_SHUTDOWN)){
struct sk_buff_head *rcvq = &sk->sk_receive_queue;
struct sk_buff *skb;
spin_lock_bh(&rcvq->lock);
while ((skb = skb_peek(rcvq)) != NULL) {
if (udp_checksum_complete(skb)) {
UDP_INC_STATS_BH(UDP_MIB_INERRORS);
__skb_unlink(skb, rcvq);
kfree_skb(skb);
} else {
skb->ip_summed = CHECKSUM_UNNECESSARY;
break;
}
}
spin_unlock_bh(&rcvq->lock);
/* nothing to see, move along */
if (skb == NULL)
mask &= ~(POLLIN | POLLRDNORM);
}
return mask;
}
struct proto udp_prot = {
.name = "UDP",
.owner = THIS_MODULE,
.close = udp_close,
.connect = ip4_datagram_connect,
.disconnect = udp_disconnect,
.ioctl = udp_ioctl,
.destroy = udp_destroy_sock,
.setsockopt = udp_setsockopt,
.getsockopt = udp_getsockopt,
.sendmsg = udp_sendmsg,
.recvmsg = udp_recvmsg,
.sendpage = udp_sendpage,
.backlog_rcv = udp_queue_rcv_skb,
.hash = udp_v4_hash,
.unhash = udp_v4_unhash,
.get_port = udp_v4_get_port,
.obj_size = sizeof(struct udp_sock),
#ifdef CONFIG_COMPAT
.compat_setsockopt = compat_udp_setsockopt,
.compat_getsockopt = compat_udp_getsockopt,
#endif
};
/* ------------------------------------------------------------------------ */
#ifdef CONFIG_PROC_FS
static struct sock *udp_get_first(struct seq_file *seq)
{
struct sock *sk;
struct udp_iter_state *state = seq->private;
for (state->bucket = 0; state->bucket < UDP_HTABLE_SIZE; ++state->bucket) {
struct hlist_node *node;
sk_for_each(sk, node, &udp_hash[state->bucket]) {
if (sk->sk_family == state->family)
goto found;
}
}
sk = NULL;
found:
return sk;
}
static struct sock *udp_get_next(struct seq_file *seq, struct sock *sk)
{
struct udp_iter_state *state = seq->private;
do {
sk = sk_next(sk);
try_again:
;
} while (sk && sk->sk_family != state->family);
if (!sk && ++state->bucket < UDP_HTABLE_SIZE) {
sk = sk_head(&udp_hash[state->bucket]);
goto try_again;
}
return sk;
}
static struct sock *udp_get_idx(struct seq_file *seq, loff_t pos)
{
struct sock *sk = udp_get_first(seq);
if (sk)
while(pos && (sk = udp_get_next(seq, sk)) != NULL)
--pos;
return pos ? NULL : sk;
}
static void *udp_seq_start(struct seq_file *seq, loff_t *pos)
{
read_lock(&udp_hash_lock);
return *pos ? udp_get_idx(seq, *pos-1) : (void *)1;
}
static void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct sock *sk;
if (v == (void *)1)
sk = udp_get_idx(seq, 0);
else
sk = udp_get_next(seq, v);
++*pos;
return sk;
}
static void udp_seq_stop(struct seq_file *seq, void *v)
{
read_unlock(&udp_hash_lock);
}
static int udp_seq_open(struct inode *inode, struct file *file)
{
struct udp_seq_afinfo *afinfo = PDE(inode)->data;
struct seq_file *seq;
int rc = -ENOMEM;
struct udp_iter_state *s = kzalloc(sizeof(*s), GFP_KERNEL);
if (!s)
goto out;
s->family = afinfo->family;
s->seq_ops.start = udp_seq_start;
s->seq_ops.next = udp_seq_next;
s->seq_ops.show = afinfo->seq_show;
s->seq_ops.stop = udp_seq_stop;
rc = seq_open(file, &s->seq_ops);
if (rc)
goto out_kfree;
seq = file->private_data;
seq->private = s;
out:
return rc;
out_kfree:
kfree(s);
goto out;
}
/* ------------------------------------------------------------------------ */
int udp_proc_register(struct udp_seq_afinfo *afinfo)
{
struct proc_dir_entry *p;
int rc = 0;
if (!afinfo)
return -EINVAL;
afinfo->seq_fops->owner = afinfo->owner;
afinfo->seq_fops->open = udp_seq_open;
afinfo->seq_fops->read = seq_read;
afinfo->seq_fops->llseek = seq_lseek;
afinfo->seq_fops->release = seq_release_private;
p = proc_net_fops_create(afinfo->name, S_IRUGO, afinfo->seq_fops);
if (p)
p->data = afinfo;
else
rc = -ENOMEM;
return rc;
}
void udp_proc_unregister(struct udp_seq_afinfo *afinfo)
{
if (!afinfo)
return;
proc_net_remove(afinfo->name);
memset(afinfo->seq_fops, 0, sizeof(*afinfo->seq_fops));
}
/* ------------------------------------------------------------------------ */
static void udp4_format_sock(struct sock *sp, char *tmpbuf, int bucket)
{
struct inet_sock *inet = inet_sk(sp);
unsigned int dest = inet->daddr;
unsigned int src = inet->rcv_saddr;
__u16 destp = ntohs(inet->dport);
__u16 srcp = ntohs(inet->sport);
sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X"
" %02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %p",
bucket, src, srcp, dest, destp, sp->sk_state,
atomic_read(&sp->sk_wmem_alloc),
atomic_read(&sp->sk_rmem_alloc),
0, 0L, 0, sock_i_uid(sp), 0, sock_i_ino(sp),
atomic_read(&sp->sk_refcnt), sp);
}
static int udp4_seq_show(struct seq_file *seq, void *v)
{
if (v == SEQ_START_TOKEN)
seq_printf(seq, "%-127s\n",
" sl local_address rem_address st tx_queue "
"rx_queue tr tm->when retrnsmt uid timeout "
"inode");
else {
char tmpbuf[129];
struct udp_iter_state *state = seq->private;
udp4_format_sock(v, tmpbuf, state->bucket);
seq_printf(seq, "%-127s\n", tmpbuf);
}
return 0;
}
/* ------------------------------------------------------------------------ */
static struct file_operations udp4_seq_fops;
static struct udp_seq_afinfo udp4_seq_afinfo = {
.owner = THIS_MODULE,
.name = "udp",
.family = AF_INET,
.seq_show = udp4_seq_show,
.seq_fops = &udp4_seq_fops,
};
int __init udp4_proc_init(void)
{
return udp_proc_register(&udp4_seq_afinfo);
}
void udp4_proc_exit(void)
{
udp_proc_unregister(&udp4_seq_afinfo);
}
#endif /* CONFIG_PROC_FS */
EXPORT_SYMBOL(udp_disconnect);
EXPORT_SYMBOL(udp_hash);
EXPORT_SYMBOL(udp_hash_lock);
EXPORT_SYMBOL(udp_ioctl);
EXPORT_SYMBOL(udp_get_port);
EXPORT_SYMBOL(udp_prot);
EXPORT_SYMBOL(udp_sendmsg);
EXPORT_SYMBOL(udp_poll);
#ifdef CONFIG_PROC_FS
EXPORT_SYMBOL(udp_proc_register);
EXPORT_SYMBOL(udp_proc_unregister);
#endif