ipx_route.c

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/*
 *  Implements the IPX routing routines.
 *  Code moved from af_ipx.c.
 *
 *  Arnaldo Carvalho de Melo <[email protected]>, 2003
 *
 *  See net/ipx/ChangeLog.
 */

#include <linux/list.h>
#include <linux/route.h>
#include <linux/slab.h>
#include <linux/spinlock.h>

#include <net/ipx.h>
#include <net/sock.h>

LIST_HEAD(ipx_routes);
DEFINE_RWLOCK(ipx_routes_lock);

extern struct ipx_interface *ipx_internal_net;

extern __be16 ipx_cksum(struct ipxhdr *packet, int length);
extern struct ipx_interface *ipxitf_find_using_net(__be32 net);
extern int ipxitf_demux_socket(struct ipx_interface *intrfc,
                   struct sk_buff *skb, int copy);
extern int ipxitf_demux_socket(struct ipx_interface *intrfc,
                   struct sk_buff *skb, int copy);
extern int ipxitf_send(struct ipx_interface *intrfc, struct sk_buff *skb,
               char *node);
extern struct ipx_interface *ipxitf_find_using_net(__be32 net);

struct ipx_route *ipxrtr_lookup(__be32 net)
{
    struct ipx_route *r;

    read_lock_bh(&ipx_routes_lock);
    list_for_each_entry(r, &ipx_routes, node)
        if (r->ir_net == net) {
            ipxrtr_hold(r);
            goto unlock;
        }
    r = NULL;
unlock:
    read_unlock_bh(&ipx_routes_lock);
    return r;
}

/*
 * Caller must hold a reference to intrfc
 */
int ipxrtr_add_route(__be32 network, struct ipx_interface *intrfc,
             unsigned char *node)
{
    struct ipx_route *rt;
    int rc;

    /* Get a route structure; either existing or create */
    rt = ipxrtr_lookup(network);
    if (!rt) {
        rt = kmalloc(sizeof(*rt), GFP_ATOMIC);
        rc = -EAGAIN;
        if (!rt)
            goto out;

        atomic_set(&rt->refcnt, 1);
        ipxrtr_hold(rt);
        write_lock_bh(&ipx_routes_lock);
        list_add(&rt->node, &ipx_routes);
        write_unlock_bh(&ipx_routes_lock);
    } else {
        rc = -EEXIST;
        if (intrfc == ipx_internal_net)
            goto out_put;
    }

    rt->ir_net  = network;
    rt->ir_intrfc   = intrfc;
    if (!node) {
        memset(rt->ir_router_node, '\0', IPX_NODE_LEN);
        rt->ir_routed = 0;
    } else {
        memcpy(rt->ir_router_node, node, IPX_NODE_LEN);
        rt->ir_routed = 1;
    }

    rc = 0;
out_put:
    ipxrtr_put(rt);
out:
    return rc;
}

void ipxrtr_del_routes(struct ipx_interface *intrfc)
{
    struct ipx_route *r, *tmp;

    write_lock_bh(&ipx_routes_lock);
    list_for_each_entry_safe(r, tmp, &ipx_routes, node)
        if (r->ir_intrfc == intrfc) {
            list_del(&r->node);
            ipxrtr_put(r);
        }
    write_unlock_bh(&ipx_routes_lock);
}

static int ipxrtr_create(struct ipx_route_definition *rd)
{
    struct ipx_interface *intrfc;
    int rc = -ENETUNREACH;

    /* Find the appropriate interface */
    intrfc = ipxitf_find_using_net(rd->ipx_router_network);
    if (!intrfc)
        goto out;
    rc = ipxrtr_add_route(rd->ipx_network, intrfc, rd->ipx_router_node);
    ipxitf_put(intrfc);
out:
    return rc;
}

static int ipxrtr_delete(__be32 net)
{
    struct ipx_route *r, *tmp;
    int rc;

    write_lock_bh(&ipx_routes_lock);
    list_for_each_entry_safe(r, tmp, &ipx_routes, node)
        if (r->ir_net == net) {
            /* Directly connected; can't lose route */
            rc = -EPERM;
            if (!r->ir_routed)
                goto out;
            list_del(&r->node);
            ipxrtr_put(r);
            rc = 0;
            goto out;
        }
    rc = -ENOENT;
out:
    write_unlock_bh(&ipx_routes_lock);
    return rc;
}

/*
 * The skb has to be unshared, we'll end up calling ipxitf_send, that'll
 * modify the packet
 */
int ipxrtr_route_skb(struct sk_buff *skb)
{
    struct ipxhdr *ipx = ipx_hdr(skb);
    struct ipx_route *r = ipxrtr_lookup(IPX_SKB_CB(skb)->ipx_dest_net);

    if (!r) {   /* no known route */
        kfree_skb(skb);
        return 0;
    }

    ipxitf_hold(r->ir_intrfc);
    ipxitf_send(r->ir_intrfc, skb, r->ir_routed ?
            r->ir_router_node : ipx->ipx_dest.node);
    ipxitf_put(r->ir_intrfc);
    ipxrtr_put(r);

    return 0;
}

/*
 * Route an outgoing frame from a socket.
 */
int ipxrtr_route_packet(struct sock *sk, struct sockaddr_ipx *usipx,
            struct iovec *iov, size_t len, int noblock)
{
    struct sk_buff *skb;
    struct ipx_sock *ipxs = ipx_sk(sk);
    struct ipx_interface *intrfc;
    struct ipxhdr *ipx;
    size_t size;
    int ipx_offset;
    struct ipx_route *rt = NULL;
    int rc;

    /* Find the appropriate interface on which to send packet */
    if (!usipx->sipx_network && ipx_primary_net) {
        usipx->sipx_network = ipx_primary_net->if_netnum;
        intrfc = ipx_primary_net;
    } else {
        rt = ipxrtr_lookup(usipx->sipx_network);
        rc = -ENETUNREACH;
        if (!rt)
            goto out;
        intrfc = rt->ir_intrfc;
    }

    ipxitf_hold(intrfc);
    ipx_offset = intrfc->if_ipx_offset;
    size = sizeof(struct ipxhdr) + len + ipx_offset;

    skb = sock_alloc_send_skb(sk, size, noblock, &rc);
    if (!skb)
        goto out_put;

    skb_reserve(skb, ipx_offset);
    skb->sk = sk;

    /* Fill in IPX header */
    skb_reset_network_header(skb);
    skb_reset_transport_header(skb);
    skb_put(skb, sizeof(struct ipxhdr));
    ipx = ipx_hdr(skb);
    ipx->ipx_pktsize = htons(len + sizeof(struct ipxhdr));
    IPX_SKB_CB(skb)->ipx_tctrl = 0;
    ipx->ipx_type    = usipx->sipx_type;

    IPX_SKB_CB(skb)->last_hop.index = -1;
#ifdef CONFIG_IPX_INTERN
    IPX_SKB_CB(skb)->ipx_source_net = ipxs->intrfc->if_netnum;
    memcpy(ipx->ipx_source.node, ipxs->node, IPX_NODE_LEN);
#else
    rc = ntohs(ipxs->port);
    if (rc == 0x453 || rc == 0x452) {
        /* RIP/SAP special handling for mars_nwe */
        IPX_SKB_CB(skb)->ipx_source_net = intrfc->if_netnum;
        memcpy(ipx->ipx_source.node, intrfc->if_node, IPX_NODE_LEN);
    } else {
        IPX_SKB_CB(skb)->ipx_source_net = ipxs->intrfc->if_netnum;
        memcpy(ipx->ipx_source.node, ipxs->intrfc->if_node,
            IPX_NODE_LEN);
    }
#endif  /* CONFIG_IPX_INTERN */
    ipx->ipx_source.sock        = ipxs->port;
    IPX_SKB_CB(skb)->ipx_dest_net   = usipx->sipx_network;
    memcpy(ipx->ipx_dest.node, usipx->sipx_node, IPX_NODE_LEN);
    ipx->ipx_dest.sock      = usipx->sipx_port;

    rc = memcpy_fromiovec(skb_put(skb, len), iov, len);
    if (rc) {
        kfree_skb(skb);
        goto out_put;
    }

    /* Apply checksum. Not allowed on 802.3 links. */
    if (sk->sk_no_check || intrfc->if_dlink_type == htons(IPX_FRAME_8023))
        ipx->ipx_checksum = htons(0xFFFF);
    else
        ipx->ipx_checksum = ipx_cksum(ipx, len + sizeof(struct ipxhdr));

    rc = ipxitf_send(intrfc, skb, (rt && rt->ir_routed) ?
             rt->ir_router_node : ipx->ipx_dest.node);
out_put:
    ipxitf_put(intrfc);
    if (rt)
        ipxrtr_put(rt);
out:
    return rc;
}

/*
 * We use a normal struct rtentry for route handling
 */
int ipxrtr_ioctl(unsigned int cmd, void __user *arg)
{
    struct rtentry rt;  /* Use these to behave like 'other' stacks */
    struct sockaddr_ipx *sg, *st;
    int rc = -EFAULT;

    if (copy_from_user(&rt, arg, sizeof(rt)))
        goto out;

    sg = (struct sockaddr_ipx *)&rt.rt_gateway;
    st = (struct sockaddr_ipx *)&rt.rt_dst;

    rc = -EINVAL;
    if (!(rt.rt_flags & RTF_GATEWAY) || /* Direct routes are fixed */
        sg->sipx_family != AF_IPX ||
        st->sipx_family != AF_IPX)
        goto out;

    switch (cmd) {
    case SIOCDELRT:
        rc = ipxrtr_delete(st->sipx_network);
        break;
    case SIOCADDRT: {
        struct ipx_route_definition f;
        f.ipx_network       = st->sipx_network;
        f.ipx_router_network    = sg->sipx_network;
        memcpy(f.ipx_router_node, sg->sipx_node, IPX_NODE_LEN);
        rc = ipxrtr_create(&f);
        break;
    }
    }

out:
    return rc;
}