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grub/grub-core/net/ip.c
Vladimir 'phcoder' Serbinenko fecdbd6b17 support ip fragmentation
2011-07-09 00:27:27 +02:00

504 lines
13 KiB
C
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/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2010,2011 Free Software Foundation, Inc.
*
* GRUB 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 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/net/ip.h>
#include <grub/misc.h>
#include <grub/net/arp.h>
#include <grub/net/udp.h>
#include <grub/net/ethernet.h>
#include <grub/net.h>
#include <grub/net/netbuff.h>
#include <grub/mm.h>
#include <grub/priority_queue.h>
#include <grub/time.h>
struct iphdr {
grub_uint8_t verhdrlen;
grub_uint8_t service;
grub_uint16_t len;
grub_uint16_t ident;
grub_uint16_t frags;
grub_uint8_t ttl;
grub_uint8_t protocol;
grub_uint16_t chksum;
grub_uint32_t src;
grub_uint32_t dest;
} __attribute__ ((packed)) ;
enum
{
DONT_FRAGMENT = 0x4000,
MORE_FRAGMENTS = 0x2000,
OFFSET_MASK = 0x1fff
};
struct ip6hdr
{
grub_uint8_t version:4, priority:4;
grub_uint8_t flow_lbl[3];
grub_uint16_t payload_len;
grub_uint8_t nexthdr;
grub_uint8_t hop_limit;
grub_uint8_t saddr[16];
grub_uint8_t daddr[16];
} __attribute__ ((packed));
static int
cmp (const void *a__, const void *b__)
{
struct grub_net_buff *a_ = *(struct grub_net_buff **) a__;
struct grub_net_buff *b_ = *(struct grub_net_buff **) b__;
struct iphdr *a = (struct iphdr *) a_->data;
struct iphdr *b = (struct iphdr *) b_->data;
/* We want the first elements to be on top. */
if ((grub_be_to_cpu16 (a->frags) & OFFSET_MASK)
< (grub_be_to_cpu16 (b->frags) & OFFSET_MASK))
return +1;
if ((grub_be_to_cpu16 (a->frags) & OFFSET_MASK)
> (grub_be_to_cpu16 (b->frags) & OFFSET_MASK))
return -1;
return 0;
}
struct reassemble
{
struct reassemble *next;
grub_uint32_t source;
grub_uint32_t dest;
grub_uint16_t id;
grub_uint8_t proto;
grub_uint64_t last_time;
grub_priority_queue_t pq;
grub_uint8_t *asm_buffer;
grub_size_t total_len;
grub_size_t cur_ptr;
};
struct reassemble *reassembles;
grub_uint16_t
grub_net_ip_chksum (void *ipv, grub_size_t len)
{
grub_uint16_t *ip = (grub_uint16_t *) ipv;
grub_uint32_t sum = 0;
for (; len >= 2; len -= 2)
{
sum += grub_be_to_cpu16 (*(ip++));
if (sum > 0xFFFF)
sum -= 0xFFFF;
}
if (len)
{
sum += *((grub_uint8_t *) ip) << 8;
if (sum > 0xFFFF)
sum -= 0xFFFF;
}
return grub_cpu_to_be16 ((~sum) & 0x0000FFFF);
}
static int id = 0x2400;
static grub_err_t
send_fragmented (struct grub_net_network_level_interface * inf,
const grub_net_network_level_address_t * target,
struct grub_net_buff * nb,
grub_net_ip_protocol_t proto,
grub_net_link_level_address_t ll_target_addr)
{
grub_size_t off = 0;
grub_size_t fraglen;
grub_err_t err;
fraglen = (inf->card->mtu - sizeof (struct iphdr)) & ~7;
id++;
while (nb->tail - nb->data)
{
grub_size_t len = fraglen;
struct grub_net_buff *nb2;
struct iphdr *iph;
if ((grub_ssize_t) len > nb->tail - nb->data)
len = nb->tail - nb->data;
nb2 = grub_netbuff_alloc (fraglen + sizeof (struct iphdr)
+ GRUB_NET_MAX_LINK_HEADER_SIZE);
if (!nb2)
return grub_errno;
err = grub_netbuff_reserve (nb2, GRUB_NET_MAX_LINK_HEADER_SIZE);
if (err)
return err;
err = grub_netbuff_put (nb2, sizeof (struct iphdr));
if (err)
return err;
iph = (struct iphdr *) nb2->data;
iph->verhdrlen = ((4 << 4) | 5);
iph->service = 0;
iph->len = grub_cpu_to_be16 (len + sizeof (struct iphdr));
iph->ident = grub_cpu_to_be16 (id);
iph->frags = grub_cpu_to_be16 (off | (((grub_ssize_t) len
== nb->tail - nb->data)
? 0 : MORE_FRAGMENTS));
iph->ttl = 0xff;
iph->protocol = proto;
iph->src = inf->address.ipv4;
iph->dest = target->ipv4;
off += len / 8;
iph->chksum = 0;
iph->chksum = grub_net_ip_chksum ((void *) nb2->data, sizeof (*iph));
err = grub_netbuff_put (nb2, len);
if (err)
return err;
grub_memcpy (iph + 1, nb->data, len);
err = grub_netbuff_pull (nb, len);
if (err)
return err;
err = send_ethernet_packet (inf, nb2, ll_target_addr,
GRUB_NET_ETHERTYPE_IP);
if (err)
return err;
}
return GRUB_ERR_NONE;
}
grub_err_t
grub_net_send_ip_packet (struct grub_net_network_level_interface * inf,
const grub_net_network_level_address_t * target,
struct grub_net_buff * nb,
grub_net_ip_protocol_t proto)
{
struct iphdr *iph;
grub_net_link_level_address_t ll_target_addr;
grub_err_t err;
COMPILE_TIME_ASSERT (GRUB_NET_OUR_IPV4_HEADER_SIZE == sizeof (*iph));
/* Determine link layer target address via ARP. */
err = grub_net_arp_resolve (inf, target, &ll_target_addr);
if (err)
return err;
if (nb->tail - nb->data + sizeof (struct iphdr) > inf->card->mtu)
return send_fragmented (inf, target, nb, proto, ll_target_addr);
grub_netbuff_push (nb, sizeof (*iph));
iph = (struct iphdr *) nb->data;
iph->verhdrlen = ((4 << 4) | 5);
iph->service = 0;
iph->len = grub_cpu_to_be16 (nb->tail - nb->data);
iph->ident = grub_cpu_to_be16 (++id);
iph->frags = 0;
iph->ttl = 0xff;
iph->protocol = proto;
iph->src = inf->address.ipv4;
iph->dest = target->ipv4;
iph->chksum = 0;
iph->chksum = grub_net_ip_chksum ((void *) nb->data, sizeof (*iph));
return send_ethernet_packet (inf, nb, ll_target_addr,
GRUB_NET_ETHERTYPE_IP);
}
static grub_err_t
handle_dgram (struct grub_net_buff *nb,
const struct grub_net_card *card,
const grub_net_link_level_address_t *hwaddress,
grub_net_ip_protocol_t proto, grub_uint32_t src,
grub_uint32_t dst)
{
struct grub_net_network_level_interface *inf = NULL;
grub_err_t err;
grub_net_network_level_address_t source;
/* DHCP needs special treatment since we don't know IP yet. */
{
struct udphdr *udph;
udph = (struct udphdr *) nb->data;
if (proto == GRUB_NET_IP_UDP && grub_be_to_cpu16 (udph->dst) == 68)
{
FOR_NET_NETWORK_LEVEL_INTERFACES (inf)
if (inf->card == card
&& inf->address.type == GRUB_NET_NETWORK_LEVEL_PROTOCOL_DHCP_RECV
&& grub_net_hwaddr_cmp (&inf->hwaddress, hwaddress) == 0)
{
err = grub_netbuff_pull (nb, sizeof (*udph));
if (err)
return err;
grub_net_process_dhcp (nb, inf->card);
grub_netbuff_free (nb);
return GRUB_ERR_NONE;
}
grub_netbuff_free (nb);
return GRUB_ERR_NONE;
}
}
FOR_NET_NETWORK_LEVEL_INTERFACES (inf)
{
if (inf->card == card
&& inf->address.type == GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4
&& inf->address.ipv4 == dst
&& grub_net_hwaddr_cmp (&inf->hwaddress, hwaddress) == 0)
break;
}
if (!inf)
{
grub_netbuff_free (nb);
return GRUB_ERR_NONE;
}
source.type = GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4;
source.ipv4 = src;
switch (proto)
{
case GRUB_NET_IP_UDP:
return grub_net_recv_udp_packet (nb, inf, &source);
case GRUB_NET_IP_ICMP:
return grub_net_recv_icmp_packet (nb, inf, &source);
default:
grub_netbuff_free (nb);
break;
}
return GRUB_ERR_NONE;
}
static void
free_rsm (struct reassemble *rsm)
{
struct grub_net_buff **nb;
while ((nb = grub_priority_queue_top (rsm->pq)))
{
grub_netbuff_free (*nb);
grub_priority_queue_pop (rsm->pq);
}
grub_free (rsm->asm_buffer);
grub_priority_queue_destroy (rsm->pq);
}
static void
free_old_fragments (void)
{
struct reassemble *rsm, **prev;
grub_uint64_t limit_time = grub_get_time_ms () - 90000;
for (prev = &reassembles, rsm = *prev; rsm; prev = &rsm->next, rsm = *prev)
if (rsm->last_time < limit_time)
{
*prev = rsm->next;
free_rsm (rsm);
}
}
grub_err_t
grub_net_recv_ip_packets (struct grub_net_buff * nb,
const struct grub_net_card * card,
const grub_net_link_level_address_t * hwaddress)
{
struct iphdr *iph = (struct iphdr *) nb->data;
grub_err_t err;
struct reassemble *rsm, **prev;
if ((iph->verhdrlen >> 4) != 4)
{
grub_dprintf ("net", "Bad IP version: %d\n", (iph->verhdrlen >> 4));
grub_netbuff_free (nb);
return GRUB_ERR_NONE;
}
if ((iph->verhdrlen & 0xf) < 5)
{
grub_dprintf ("net", "IP header too short: %d\n",
(iph->verhdrlen & 0xf));
grub_netbuff_free (nb);
return GRUB_ERR_NONE;
}
if (nb->tail - nb->data < (grub_ssize_t) ((iph->verhdrlen & 0xf)
* sizeof (grub_uint32_t)))
{
grub_dprintf ("net", "IP packet too short: %d\n",
(iph->verhdrlen & 0xf));
grub_netbuff_free (nb);
return GRUB_ERR_NONE;
}
/* Check size. */
{
grub_size_t expected_size = grub_be_to_cpu16 (iph->len);
grub_size_t actual_size = (nb->tail - nb->data);
if (actual_size > expected_size)
{
err = grub_netbuff_unput (nb, actual_size - expected_size);
if (err)
{
grub_netbuff_free (nb);
return err;
}
}
if (actual_size < expected_size)
{
grub_dprintf ("net", "Cut IP packet actual: %" PRIuGRUB_SIZE
", expected %" PRIuGRUB_SIZE "\n", actual_size,
expected_size);
grub_netbuff_free (nb);
return GRUB_ERR_NONE;
}
}
/* Unfragmented packet. Good. */
if (((grub_be_to_cpu16 (iph->frags) & MORE_FRAGMENTS) == 0)
&& (grub_be_to_cpu16 (iph->frags) & OFFSET_MASK) == 0)
{
err = grub_netbuff_pull (nb, ((iph->verhdrlen & 0xf)
* sizeof (grub_uint32_t)));
if (err)
{
grub_netbuff_free (nb);
return err;
}
return handle_dgram (nb, card, hwaddress, iph->protocol,
iph->src, iph->dest);
}
for (prev = &reassembles, rsm = *prev; rsm; prev = &rsm->next, rsm = *prev)
if (rsm->source == iph->src && rsm->dest == iph->dest
&& rsm->id == iph->ident && rsm->proto == iph->protocol)
break;
if (!rsm)
{
rsm = grub_malloc (sizeof (*rsm));
if (!rsm)
return grub_errno;
rsm->source = iph->src;
rsm->dest = iph->dest;
rsm->id = iph->ident;
rsm->proto = iph->protocol;
rsm->next = reassembles;
reassembles = rsm;
prev = &reassembles;
rsm->pq = grub_priority_queue_new (sizeof (struct grub_net_buff **), cmp);
if (!rsm->pq)
{
grub_free (rsm);
return grub_errno;
}
rsm->asm_buffer = 0;
rsm->total_len = 0;
rsm->cur_ptr = 0;
}
rsm->last_time = grub_get_time_ms ();
free_old_fragments ();
err = grub_priority_queue_push (rsm->pq, &nb);
if (err)
return err;
if (!(grub_be_to_cpu16 (iph->frags) & MORE_FRAGMENTS))
{
rsm->total_len = (8 * (grub_be_to_cpu16 (iph->frags) & OFFSET_MASK)
+ (nb->tail - nb->data));
rsm->total_len -= ((iph->verhdrlen & 0xf) * sizeof (grub_uint32_t));
rsm->asm_buffer = grub_zalloc (rsm->total_len);
if (!rsm->asm_buffer)
{
*prev = rsm->next;
free_rsm (rsm);
return grub_errno;
}
}
if (!rsm->asm_buffer)
return GRUB_ERR_NONE;
while (1)
{
struct grub_net_buff **nb_top_p, *nb_top;
grub_size_t copy;
grub_uint8_t *res;
grub_size_t res_len;
struct grub_net_buff *ret;
grub_net_ip_protocol_t proto;
grub_uint32_t src;
grub_uint32_t dst;
nb_top_p = grub_priority_queue_top (rsm->pq);
if (!nb_top_p)
return GRUB_ERR_NONE;
nb_top = *nb_top_p;
grub_priority_queue_pop (rsm->pq);
iph = (struct iphdr *) nb_top->data;
err = grub_netbuff_pull (nb_top, ((iph->verhdrlen & 0xf)
* sizeof (grub_uint32_t)));
if (err)
{
grub_netbuff_free (nb_top);
return err;
}
if (rsm->cur_ptr < (grub_size_t) 8 * (grub_be_to_cpu16 (iph->frags)
& OFFSET_MASK))
return GRUB_ERR_NONE;
rsm->cur_ptr = (8 * (grub_be_to_cpu16 (iph->frags) & OFFSET_MASK)
+ (nb_top->tail - nb_top->head));
if ((grub_size_t) 8 * (grub_be_to_cpu16 (iph->frags) & OFFSET_MASK)
>= rsm->total_len)
{
grub_netbuff_free (nb_top);
continue;
}
copy = nb_top->tail - nb_top->data;
if (rsm->total_len - 8 * (grub_be_to_cpu16 (iph->frags) & OFFSET_MASK)
< copy)
copy = rsm->total_len - 8 * (grub_be_to_cpu16 (iph->frags)
& OFFSET_MASK);
grub_memcpy (&rsm->asm_buffer[8 * (grub_be_to_cpu16 (iph->frags)
& OFFSET_MASK)],
nb_top->data, copy);
if ((grub_be_to_cpu16 (iph->frags) & MORE_FRAGMENTS))
continue;
res = rsm->asm_buffer;
proto = rsm->proto;
src = rsm->source;
dst = rsm->dest;
rsm->asm_buffer = 0;
res_len = rsm->total_len;
*prev = rsm->next;
free_rsm (rsm);
ret = grub_malloc (sizeof (*ret));
if (!ret)
{
grub_free (res);
return grub_errno;
}
ret->data = ret->head = res;
ret->tail = ret->end = res + res_len;
return handle_dgram (ret, card, hwaddress, proto, src, dst);
}
return GRUB_ERR_NONE;
}
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