/*
 * 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 1.39 1998/11/08 11:17:04 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 <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/checksum.h>

#ifdef CONFIG_IP_MROUTE
struct sock *mroute_socket=NULL;
#endif

struct sock *raw_v4_htable[RAWV4_HTABLE_SIZE];

static void raw_v4_hash(struct sock *sk)
{
        struct sock **skp;
        int num = sk->num;

        num &= (RAWV4_HTABLE_SIZE - 1);
        skp = &raw_v4_htable[num];
        SOCKHASH_LOCK();
        sk->next = *skp;
        *skp = sk;
        sk->hashent = num;
        SOCKHASH_UNLOCK();
}

static void raw_v4_unhash(struct sock *sk)
{
        struct sock **skp;
        int num = sk->num;

        num &= (RAWV4_HTABLE_SIZE - 1);
        skp = &raw_v4_htable[num];

        SOCKHASH_LOCK();
        while(*skp != NULL) {
                if(*skp == sk) {
                        *skp = sk->next;
                        break;
                }
                skp = &((*skp)->next);
        }
        SOCKHASH_UNLOCK();
}

static void raw_v4_rehash(struct sock *sk)
{
        struct sock **skp;
        int num = sk->num;
        int oldnum = sk->hashent;

        num &= (RAWV4_HTABLE_SIZE - 1);
        skp = &raw_v4_htable[oldnum];

        SOCKHASH_LOCK();
        while(*skp != NULL) {
                if(*skp == sk) {
                        *skp = sk->next;
                        break;
                }
                skp = &((*skp)->next);
        }
        sk->next = raw_v4_htable[num];
        raw_v4_htable[num] = sk;
        sk->hashent = num;
        SOCKHASH_UNLOCK();
}

/* Grumble... icmp and ip_input want to get at this... */
struct sock *raw_v4_lookup(struct sock *sk, unsigned short num,
                           unsigned long raddr, unsigned long laddr, int dif)
{
        struct sock *s = sk;

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

void raw_err (struct sock *sk, struct sk_buff *skb)
{
        int type = skb->h.icmph->type;
        int code = skb->h.icmph->code;
        u32 info = 0;
        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->ip_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;
                info = ntohl(skb->h.icmph->un.gateway)>>24;
                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->ip_pmtudisc != IP_PMTUDISC_DONT);
                        err = EMSGSIZE;
                        info = ntohs(skb->h.icmph->un.frag.mtu);
                }
        }

        if (sk->ip_recverr)
                ip_icmp_error(sk, skb, err, 0, info, (u8 *)(skb->h.icmph + 1));
                
        if (sk->ip_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_statistics.IpInDiscards++;
                kfree_skb(skb);
                return -1;
        }

        ip_statistics.IpInDelivers++;
        return 0;
}

/*
 *      This should be the easiest of all, all we do is
 *      copy it into a buffer. All demultiplexing is done
 *      in ip.c
 */

int raw_rcv(struct sock *sk, struct sk_buff *skb)
{
        /* Now we need to copy this into memory. */
        skb_trim(skb, ntohs(skb->nh.iph->tot_len));
        
        skb->h.raw = skb->nh.raw;

        raw_rcv_skb(sk, skb);
        return 0;
}

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

/*
 *      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==0) {
                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)
                        iph->id = htons(ip_id_count++);
                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
         */

        if (len < 0 || len > 0xFFFF)
                return -EMSGSIZE;

        /*
         *      Check the flags.
         */

        if (msg->msg_flags & MSG_OOB)           /* Mirror BSD error message compatibility */
                return -EOPNOTSUPP;
                         
        if (msg->msg_flags & ~(MSG_DONTROUTE|MSG_DONTWAIT))
                return(-EINVAL);

        /*
         *      Get and verify the address. 
         */

        if (msg->msg_namelen) {
                struct sockaddr_in *usin = (struct sockaddr_in*)msg->msg_name;
                if (msg->msg_namelen < sizeof(*usin))
                        return(-EINVAL);
                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);
                        if (usin->sin_family)
                                return -EINVAL;
                }
                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 {
                if (sk->state != TCP_ESTABLISHED) 
                        return(-EINVAL);
                daddr = sk->daddr;
        }

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

        if (msg->msg_controllen) {
                int tmp = ip_cmsg_send(msg, &ipc);
                if (tmp)
                        return tmp;
                if (ipc.opt)
                        free=1;
        }

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

        if (!ipc.opt)
                ipc.opt = sk->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->ip_hdrincl)
                        goto done;
                if (ipc.opt->srr) {
                        if (!daddr)
                                goto done;
                        daddr = ipc.opt->faddr;
                }
        }
        tos = RT_TOS(sk->ip_tos) | sk->localroute;
        if (msg->msg_flags&MSG_DONTROUTE)
                tos |= RTO_ONLINK;

        if (MULTICAST(daddr)) {
                if (!ipc.oif)
                        ipc.oif = sk->ip_mc_index;
                if (!rfh.saddr)
                        rfh.saddr = sk->ip_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;

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

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

        return err<0 ? err : len;
}

static void raw_close(struct sock *sk, long timeout)
{
        /* Observation: when raw_close is called, processes have
           no access to socket anymore. But net still has.
           Step one, detach it from networking:

           A. Remove from hash tables.
         */
        sk->state = TCP_CLOSE;
        raw_v4_unhash(sk);
        /*
           B. Raw sockets may have direct kernel refereneces. Kill them.
         */
        ip_ra_control(sk, 0, NULL);

        /* In this point socket cannot receive new packets anymore */


        /* But we still have packets pending on receive
           queue and probably, our own packets waiting in device queues.
           sock_destroy will drain receive queue, but transmitted
           packets will delay socket destruction.
           Set sk->dead=1 in order to prevent wakeups, when these
           packet will be freed.
         */
        sk->dead=1;
        destroy_sock(sk);

        /* That's all. No races here. */
}

/* 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 chk_addr_ret;

        if((sk->state != TCP_CLOSE) || (addr_len < sizeof(struct sockaddr_in)))
                return -EINVAL;
        chk_addr_ret = inet_addr_type(addr->sin_addr.s_addr);
        if(addr->sin_addr.s_addr != 0 && chk_addr_ret != RTN_LOCAL &&
           chk_addr_ret != RTN_MULTICAST && chk_addr_ret != RTN_BROADCAST) {
#ifdef CONFIG_IP_TRANSPARENT_PROXY
                /* Superuser may bind to any address to allow transparent proxying. */
                if(chk_addr_ret != RTN_UNICAST || !capable(CAP_NET_ADMIN))
#endif
                        return -EADDRNOTAVAIL;
        }
        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 */
        dst_release(xchg(&sk->dst_cache, NULL));
        return 0;
}

/*
 *      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;
        struct sk_buff *skb;
        int err;
        struct sockaddr_in *sin=(struct sockaddr_in *)msg->msg_name;

        if (flags & MSG_OOB)
                return -EOPNOTSUPP;

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

        if (flags & MSG_ERRQUEUE)
                return ip_recv_error(sk, msg, len);

        skb=skb_recv_datagram(sk,flags,noblock,&err);
        if(skb==NULL)
                return err;

        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;

        sk->stamp=skb->stamp;

        /* Copy the address. */
        if (sin) {
                sin->sin_family = AF_INET;
                sin->sin_addr.s_addr = skb->nh.iph->saddr;
        }
        if (sk->ip_cmsg_flags)
                ip_cmsg_recv(msg, skb);
done:
        skb_free_datagram(sk, skb);
        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;

        if (get_user(len,optlen))
                return -EFAULT;
        if (len > sizeof(struct icmp_filter))
                len = sizeof(struct icmp_filter);
        if (put_user(len, optlen))
                return -EFAULT;
        if (copy_to_user(optval, &sk->tp_pinfo.tp_raw4.filter, len))
                return -EFAULT;
        return 0;
}

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);

        switch (optname) {
        case ICMP_FILTER:
                if (sk->num != IPPROTO_ICMP)
                        return -EOPNOTSUPP;
                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);

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

        return -ENOPROTOOPT;
}

struct proto raw_prot = {
        (struct sock *)&raw_prot,       /* sklist_next */
        (struct sock *)&raw_prot,       /* sklist_prev */
        raw_close,                      /* close */
        udp_connect,                    /* connect */
        NULL,                           /* accept */
        NULL,                           /* retransmit */
        NULL,                           /* write_wakeup */
        NULL,                           /* read_wakeup */
        datagram_poll,                  /* poll */
#ifdef CONFIG_IP_MROUTE
        ipmr_ioctl,                     /* ioctl */
#else
        NULL,                           /* ioctl */
#endif
        raw_init,                       /* init */
        NULL,                           /* destroy */
        NULL,                           /* shutdown */
        raw_setsockopt,                 /* setsockopt */
        raw_getsockopt,                 /* getsockopt */
        raw_sendmsg,                    /* sendmsg */
        raw_recvmsg,                    /* recvmsg */
        raw_bind,                       /* bind */
        raw_rcv_skb,                    /* backlog_rcv */
        raw_v4_hash,                    /* hash */
        raw_v4_unhash,                  /* unhash */
        raw_v4_rehash,                  /* rehash */
        NULL,                           /* good_socknum */
        NULL,                           /* verify_bind */
        128,                            /* max_header */
        0,                              /* retransmits */
        "RAW",                          /* name */
        0,                              /* inuse */
        0                               /* highestinuse */
};