raw.c

Go to the documentation of this file.

/*
 * 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.
 *
 *              RAW - implementation of IP "raw" sockets.
 *
 * Version:     $Id: raw.c,v 1.63.2.1 2002/03/05 12:47:34 davem Exp $
 *
 * Authors:     Ross Biro, <bir7@leland.Stanford.Edu>
 *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *
 * Fixes:
 *              Alan Cox        :       verify_area() fixed up
 *              Alan Cox        :       ICMP error handling
 *              Alan Cox        :       EMSGSIZE if you send too big a packet
 *              Alan Cox        :       Now uses generic datagrams and shared
 *                                      skbuff library. No more peek crashes,
 *                                      no more backlogs
 *              Alan Cox        :       Checks sk->broadcast.
 *              Alan Cox        :       Uses skb_free_datagram/skb_copy_datagram
 *              Alan Cox        :       Raw passes ip options too
 *              Alan Cox        :       Setsocketopt added
 *              Alan Cox        :       Fixed error return for broadcasts
 *              Alan Cox        :       Removed wake_up calls
 *              Alan Cox        :       Use ttl/tos
 *              Alan Cox        :       Cleaned up old debugging
 *              Alan Cox        :       Use new kernel side addresses
 *      Arnt Gulbrandsen        :       Fixed MSG_DONTROUTE in raw sockets.
 *              Alan Cox        :       BSD style RAW socket demultiplexing.
 *              Alan Cox        :       Beginnings of mrouted support.
 *              Alan Cox        :       Added IP_HDRINCL option.
 *              Alan Cox        :       Skip broadcast check if BSDism set.
 *              David S. Miller :       New socket lookup architecture.
 *
 *              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 <linux/config.h> 
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/ioctls.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/fcntl.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/mroute.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/icmp.h>
#include <net/udp.h>
#include <net/raw.h>
#include <net/inet_common.h>
#include <net/checksum.h>

struct sock *raw_v4_htable[RAWV4_HTABLE_SIZE];
rwlock_t raw_v4_lock = RW_LOCK_UNLOCKED;

static void raw_v4_hash(struct sock *sk)
{
        struct sock **skp = &raw_v4_htable[sk->num & (RAWV4_HTABLE_SIZE - 1)];

        write_lock_bh(&raw_v4_lock);
        if ((sk->next = *skp) != NULL)
                (*skp)->pprev = &sk->next;
        *skp = sk;
        sk->pprev = skp;
        sock_prot_inc_use(sk->prot);
        sock_hold(sk);
        write_unlock_bh(&raw_v4_lock);
}

static void raw_v4_unhash(struct sock *sk)
{
        write_lock_bh(&raw_v4_lock);
        if (sk->pprev) {
                if (sk->next)
                        sk->next->pprev = sk->pprev;
                *sk->pprev = sk->next;
                sk->pprev = NULL;
                sock_prot_dec_use(sk->prot);
                __sock_put(sk);
        }
        write_unlock_bh(&raw_v4_lock);
}

struct sock *__raw_v4_lookup(struct sock *sk, unsigned short num,
                             unsigned long raddr, unsigned long laddr,
                             int dif)
{
        struct sock *s = sk;

        for (s = sk; s; s = s->next) {
                if (s->num == num                               &&
                    !(s->daddr && s->daddr != raddr)            &&
                    !(s->rcv_saddr && s->rcv_saddr != laddr)    &&
                    !(s->bound_dev_if && s->bound_dev_if != dif))
                        break; /* gotcha */
        }
        return s;
}

/*
 *      0 - deliver
 *      1 - block
 */
static __inline__ int icmp_filter(struct sock *sk, struct sk_buff *skb)
{
        int type;

        type = skb->h.icmph->type;
        if (type < 32) {
                __u32 data = sk->tp_pinfo.tp_raw4.filter.data;

                return ((1 << type) & data) != 0;
        }

        /* Do not block unknown ICMP types */
        return 0;
}

/* IP input processing comes here for RAW socket delivery.
 * This is fun as to avoid copies we want to make no surplus
 * copies.
 *
 * RFC 1122: SHOULD pass TOS value up to the transport layer.
 * -> It does. And not only TOS, but all IP header.
 */
struct sock *raw_v4_input(struct sk_buff *skb, struct iphdr *iph, int hash)
{
        struct sock *sk;

        read_lock(&raw_v4_lock);
        if ((sk = raw_v4_htable[hash]) == NULL)
                goto out;
        sk = __raw_v4_lookup(sk, iph->protocol,
                             iph->saddr, iph->daddr,
                             skb->dev->ifindex);

        while (sk) {
                struct sock *sknext = __raw_v4_lookup(sk->next, iph->protocol,
                                                      iph->saddr, iph->daddr,
                                                      skb->dev->ifindex);
                if (iph->protocol != IPPROTO_ICMP ||
                    !icmp_filter(sk, skb)) {
                        struct sk_buff *clone;

                        if (!sknext)
                                break;
                        clone = skb_clone(skb, GFP_ATOMIC);
                        /* Not releasing hash table! */
                        if (clone)
                                raw_rcv(sk, clone);
                }
                sk = sknext;
        }
out:
        if (sk)
                sock_hold(sk);
        read_unlock(&raw_v4_lock);

        return sk;
}

void raw_err (struct sock *sk, struct sk_buff *skb, u32 info)
{
        int type = skb->h.icmph->type;
        int code = skb->h.icmph->code;
        int err = 0;
        int harderr = 0;

        /* Report error on raw socket, if:
           1. User requested ip_recverr.
           2. Socket is connected (otherwise the error indication
              is useless without ip_recverr and error is hard.
         */
        if (!sk->protinfo.af_inet.recverr && sk->state != TCP_ESTABLISHED)
                return;

        switch (type) {
        default:
        case ICMP_TIME_EXCEEDED:
                err = EHOSTUNREACH;
                break;
        case ICMP_SOURCE_QUENCH:
                return;
        case ICMP_PARAMETERPROB:
                err = EPROTO;
                harderr = 1;
                break;
        case ICMP_DEST_UNREACH:
                err = EHOSTUNREACH;
                if (code > NR_ICMP_UNREACH)
                        break;
                err = icmp_err_convert[code].errno;
                harderr = icmp_err_convert[code].fatal;
                if (code == ICMP_FRAG_NEEDED) {
                        harderr = sk->protinfo.af_inet.pmtudisc !=
                                        IP_PMTUDISC_DONT;
                        err = EMSGSIZE;
                }
        }

        if (sk->protinfo.af_inet.recverr) {
                struct iphdr *iph = (struct iphdr*)skb->data;
                u8 *payload = skb->data + (iph->ihl << 2);

                if (sk->protinfo.af_inet.hdrincl)
                        payload = skb->data;
                ip_icmp_error(sk, skb, err, 0, info, payload);
        }

        if (sk->protinfo.af_inet.recverr || harderr) {
                sk->err = err;
                sk->error_report(sk);
        }
}

static int raw_rcv_skb(struct sock * sk, struct sk_buff * skb)
{
        /* Charge it to the socket. */
        
        if (sock_queue_rcv_skb(sk, skb) < 0) {
                IP_INC_STATS(IpInDiscards);
                kfree_skb(skb);
                return NET_RX_DROP;
        }

        IP_INC_STATS(IpInDelivers);
        return NET_RX_SUCCESS;
}

int raw_rcv(struct sock *sk, struct sk_buff *skb)
{
        skb_push(skb, skb->data - skb->nh.raw);

        raw_rcv_skb(sk, skb);
        return 0;
}

struct rawfakehdr 
{
        struct  iovec *iov;
        u32     saddr;
        struct  dst_entry *dst;
};

/*
 *      Send a RAW IP packet.
 */

/*
 *      Callback support is trivial for SOCK_RAW
 */
  
static int raw_getfrag(const void *p, char *to, unsigned int offset,
                        unsigned int fraglen)
{
        struct rawfakehdr *rfh = (struct rawfakehdr *) p;
        return memcpy_fromiovecend(to, rfh->iov, offset, fraglen);
}

/*
 *      IPPROTO_RAW needs extra work.
 */
 
static int raw_getrawfrag(const void *p, char *to, unsigned int offset,
                                unsigned int fraglen)
{
        struct rawfakehdr *rfh = (struct rawfakehdr *) p;

        if (memcpy_fromiovecend(to, rfh->iov, offset, fraglen))
                return -EFAULT;

        if (!offset) {
                struct iphdr *iph = (struct iphdr *)to;
                if (!iph->saddr)
                        iph->saddr = rfh->saddr;
                iph->check   = 0;
                iph->tot_len = htons(fraglen); /* This is right as you can't
                                                  frag RAW packets */
                /*
                 *      Deliberate breach of modularity to keep 
                 *      ip_build_xmit clean (well less messy).
                 */
                if (!iph->id)
                        ip_select_ident(iph, rfh->dst, NULL);
                iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
        }
        return 0;
}

static int raw_sendmsg(struct sock *sk, struct msghdr *msg, int len)
{
        struct ipcm_cookie ipc;
        struct rawfakehdr rfh;
        struct rtable *rt = NULL;
        int free = 0;
        u32 daddr;
        u8  tos;
        int err;

        /* This check is ONLY to check for arithmetic overflow
           on integer(!) len. Not more! Real check will be made
           in ip_build_xmit --ANK

           BTW socket.c -> af_*.c -> ... make multiple
           invalid conversions size_t -> int. We MUST repair it f.e.
           by replacing all of them with size_t and revise all
           the places sort of len += sizeof(struct iphdr)
           If len was ULONG_MAX-10 it would be cathastrophe  --ANK
         */

        err = -EMSGSIZE;
        if (len < 0 || len > 0xFFFF)
                goto out;

        /*
         *      Check the flags.
         */

        err = -EOPNOTSUPP;
        if (msg->msg_flags & MSG_OOB)   /* Mirror BSD error message */
                goto out;               /* compatibility */
                         
        /*
         *      Get and verify the address. 
         */

        if (msg->msg_namelen) {
                struct sockaddr_in *usin = (struct sockaddr_in*)msg->msg_name;
                err = -EINVAL;
                if (msg->msg_namelen < sizeof(*usin))
                        goto out;
                if (usin->sin_family != AF_INET) {
                        static int complained;
                        if (!complained++)
                                printk(KERN_INFO "%s forgot to set AF_INET in "
                                                 "raw sendmsg. Fix it!\n",
                                                 current->comm);
                        err = -EINVAL;
                        if (usin->sin_family)
                                goto out;
                }
                daddr = usin->sin_addr.s_addr;
                /* ANK: I did not forget to get protocol from port field.
                 * I just do not know, who uses this weirdness.
                 * IP_HDRINCL is much more convenient.
                 */
        } else {
                err = -EDESTADDRREQ;
                if (sk->state != TCP_ESTABLISHED) 
                        goto out;
                daddr = sk->daddr;
        }

        ipc.addr = sk->saddr;
        ipc.opt = NULL;
        ipc.oif = sk->bound_dev_if;

        if (msg->msg_controllen) {
                err = ip_cmsg_send(msg, &ipc);
                if (err)
                        goto out;
                if (ipc.opt)
                        free = 1;
        }

        rfh.saddr = ipc.addr;
        ipc.addr = daddr;

        if (!ipc.opt)
                ipc.opt = sk->protinfo.af_inet.opt;

        if (ipc.opt) {
                err = -EINVAL;
                /* Linux does not mangle headers on raw sockets,
                 * so that IP options + IP_HDRINCL is non-sense.
                 */
                if (sk->protinfo.af_inet.hdrincl)
                        goto done;
                if (ipc.opt->srr) {
                        if (!daddr)
                                goto done;
                        daddr = ipc.opt->faddr;
                }
        }
        tos = RT_TOS(sk->protinfo.af_inet.tos) | sk->localroute;
        if (msg->msg_flags & MSG_DONTROUTE)
                tos |= RTO_ONLINK;

        if (MULTICAST(daddr)) {
                if (!ipc.oif)
                        ipc.oif = sk->protinfo.af_inet.mc_index;
                if (!rfh.saddr)
                        rfh.saddr = sk->protinfo.af_inet.mc_addr;
        }

        err = ip_route_output(&rt, daddr, rfh.saddr, tos, ipc.oif);

        if (err)
                goto done;

        err = -EACCES;
        if (rt->rt_flags & RTCF_BROADCAST && !sk->broadcast)
                goto done;

        if (msg->msg_flags & MSG_CONFIRM)
                goto do_confirm;
back_from_confirm:

        rfh.iov         = msg->msg_iov;
        rfh.saddr       = rt->rt_src;
        rfh.dst         = &rt->u.dst;
        if (!ipc.addr)
                ipc.addr = rt->rt_dst;
        err = ip_build_xmit(sk, sk->protinfo.af_inet.hdrincl ? raw_getrawfrag :
                            raw_getfrag, &rfh, len, &ipc, rt, msg->msg_flags);

done:
        if (free)
                kfree(ipc.opt);
        ip_rt_put(rt);

out:    return err < 0 ? err : len;

do_confirm:
        dst_confirm(&rt->u.dst);
        if (!(msg->msg_flags & MSG_PROBE) || len)
                goto back_from_confirm;
        err = 0;
        goto done;
}

static void raw_close(struct sock *sk, long timeout)
{
        /*
         * Raw sockets may have direct kernel refereneces. Kill them.
         */
        ip_ra_control(sk, 0, NULL);

        inet_sock_release(sk);
}

/* This gets rid of all the nasties in af_inet. -DaveM */
static int raw_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
        struct sockaddr_in *addr = (struct sockaddr_in *) uaddr;
        int ret = -EINVAL;
        int chk_addr_ret;

        if (sk->state != TCP_CLOSE || addr_len < sizeof(struct sockaddr_in))
                goto out;
        chk_addr_ret = inet_addr_type(addr->sin_addr.s_addr);
        ret = -EADDRNOTAVAIL;
        if (addr->sin_addr.s_addr && chk_addr_ret != RTN_LOCAL &&
            chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST)
                goto out;
        sk->rcv_saddr = sk->saddr = addr->sin_addr.s_addr;
        if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
                sk->saddr = 0;  /* Use device */
        sk_dst_reset(sk);
        ret = 0;
out:    return ret;
}

/*
 *      This should be easy, if there is something there
 *      we return it, otherwise we block.
 */

int raw_recvmsg(struct sock *sk, struct msghdr *msg, int len,
                int noblock, int flags, int *addr_len)
{
        int copied = 0;
        int err = -EOPNOTSUPP;
        struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
        struct sk_buff *skb;

        if (flags & MSG_OOB)
                goto out;

        if (addr_len)
                *addr_len = sizeof(*sin);

        if (flags & MSG_ERRQUEUE) {
                err = ip_recv_error(sk, msg, len);
                goto out;
        }

        skb = skb_recv_datagram(sk, flags, noblock, &err);
        if (!skb)
                goto out;

        copied = skb->len;
        if (len < copied) {
                msg->msg_flags |= MSG_TRUNC;
                copied = len;
        }

        err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
        if (err)
                goto done;

        sock_recv_timestamp(msg, sk, skb);

        /* Copy the address. */
        if (sin) {
                sin->sin_family = AF_INET;
                sin->sin_addr.s_addr = skb->nh.iph->saddr;
                memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
        }
        if (sk->protinfo.af_inet.cmsg_flags)
                ip_cmsg_recv(msg, skb);
done:
        skb_free_datagram(sk, skb);
out:    return err ? : copied;
}

static int raw_init(struct sock *sk)
{
        struct raw_opt *tp = &(sk->tp_pinfo.tp_raw4);
        if (sk->num == IPPROTO_ICMP)
                memset(&tp->filter, 0, sizeof(tp->filter));
        return 0;
}

static int raw_seticmpfilter(struct sock *sk, char *optval, int optlen)
{
        if (optlen > sizeof(struct icmp_filter))
                optlen = sizeof(struct icmp_filter);
        if (copy_from_user(&sk->tp_pinfo.tp_raw4.filter, optval, optlen))
                return -EFAULT;
        return 0;
}

static int raw_geticmpfilter(struct sock *sk, char *optval, int *optlen)
{
        int len, ret = -EFAULT;

        if (get_user(len, optlen))
                goto out;
        ret = -EINVAL;
        if (len < 0)
                goto out;
        if (len > sizeof(struct icmp_filter))
                len = sizeof(struct icmp_filter);
        ret = -EFAULT;
        if (put_user(len, optlen) ||
            copy_to_user(optval, &sk->tp_pinfo.tp_raw4.filter, len))
                goto out;
        ret = 0;
out:    return ret;
}

static int raw_setsockopt(struct sock *sk, int level, int optname, 
                          char *optval, int optlen)
{
        if (level != SOL_RAW)
                return ip_setsockopt(sk, level, optname, optval, optlen);

        if (optname == ICMP_FILTER) {
                if (sk->num != IPPROTO_ICMP)
                        return -EOPNOTSUPP;
                else
                        return raw_seticmpfilter(sk, optval, optlen);
        }
        return -ENOPROTOOPT;
}

static int raw_getsockopt(struct sock *sk, int level, int optname, 
                          char *optval, int *optlen)
{
        if (level != SOL_RAW)
                return ip_getsockopt(sk, level, optname, optval, optlen);

        if (optname == ICMP_FILTER) {
                if (sk->num != IPPROTO_ICMP)
                        return -EOPNOTSUPP;
                else
                        return raw_geticmpfilter(sk, optval, optlen);
        }
        return -ENOPROTOOPT;
}

static int raw_ioctl(struct sock *sk, int cmd, unsigned long arg)
{
        switch (cmd) {
                case SIOCOUTQ: {
                        int amount = atomic_read(&sk->wmem_alloc);
                        return put_user(amount, (int *)arg);
                }
                case SIOCINQ: {
                        struct sk_buff *skb;
                        int amount = 0;

                        spin_lock_irq(&sk->receive_queue.lock);
                        skb = skb_peek(&sk->receive_queue);
                        if (skb != NULL)
                                amount = skb->len;
                        spin_unlock_irq(&sk->receive_queue.lock);
                        return put_user(amount, (int *)arg);
                }

                default:
#ifdef CONFIG_IP_MROUTE
                        return ipmr_ioctl(sk, cmd, arg);
#else
                        return -ENOIOCTLCMD;
#endif
        }
}

static void get_raw_sock(struct sock *sp, char *tmpbuf, int i)
{
        unsigned int dest = sp->daddr,
                     src = sp->rcv_saddr;
        __u16 destp = 0,
              srcp  = sp->num;

        sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X"
                " %02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %p",
                i, src, srcp, dest, destp, sp->state, 
                atomic_read(&sp->wmem_alloc), atomic_read(&sp->rmem_alloc),
                0, 0L, 0,
                sock_i_uid(sp), 0,
                sock_i_ino(sp),
                atomic_read(&sp->refcnt), sp);
}

int raw_get_info(char *buffer, char **start, off_t offset, int length)
{
        int len = 0, num = 0, i;
        off_t pos = 128;
        off_t begin;
        char tmpbuf[129];

        if (offset < 128) 
                len += sprintf(buffer, "%-127s\n",
                               "  sl  local_address rem_address   st tx_queue "
                               "rx_queue tr tm->when retrnsmt   uid  timeout "
                               "inode");
        read_lock(&raw_v4_lock);
        for (i = 0; i < RAWV4_HTABLE_SIZE; i++) {
                struct sock *sk;

                for (sk = raw_v4_htable[i]; sk; sk = sk->next, num++) {
                        if (sk->family != PF_INET)
                                continue;
                        pos += 128;
                        if (pos <= offset)
                                continue;
                        get_raw_sock(sk, tmpbuf, i);
                        len += sprintf(buffer + len, "%-127s\n", tmpbuf);
                        if (len >= length)
                                goto out;
                }
        }
out:
        read_unlock(&raw_v4_lock);
        begin = len - (pos - offset);
        *start = buffer + begin;
        len -= begin;
        if (len > length)
                len = length;
        if (len < 0)
                len = 0; 
        return len;
}

struct proto raw_prot = {
        name:           "RAW",
        close:          raw_close,
        connect:        udp_connect,
        disconnect:     udp_disconnect,
        ioctl:          raw_ioctl,
        init:           raw_init,
        setsockopt:     raw_setsockopt,
        getsockopt:     raw_getsockopt,
        sendmsg:        raw_sendmsg,
        recvmsg:        raw_recvmsg,
        bind:           raw_bind,
        backlog_rcv:    raw_rcv_skb,
        hash:           raw_v4_hash,
        unhash:         raw_v4_unhash,
};

---