/* Reserves 'size' bytes of headroom so that they can be later allocated with
* dp_packet_push_uninit() without reallocating the dp_packet. */
void
dp_packet_reserve(struct dp_packet *b, size_t size)
{
ovs_assert(!dp_packet_size(b));
dp_packet_prealloc_tailroom(b, size);
dp_packet_set_data(b, (char*)dp_packet_data(b) + size);
}
/* Reserves 'headroom' bytes at the head and 'tailroom' at the end so that
* they can be later allocated with dp_packet_push_uninit() or
* dp_packet_put_uninit() without reallocating the dp_packet. */
void
dp_packet_reserve_with_tailroom(struct dp_packet *b, size_t headroom,
size_t tailroom)
{
ovs_assert(!dp_packet_size(b));
dp_packet_prealloc_tailroom(b, headroom + tailroom);
dp_packet_set_data(b, (char*)dp_packet_data(b) + headroom);
}
/* Appends 'size' bytes of data to the tail end of 'b', reallocating and
* copying its data if necessary. Returns a pointer to the first byte of the
* new data, which is left uninitialized. */
void *
dp_packet_put_uninit(struct dp_packet *b, size_t size)
{
void *p;
dp_packet_prealloc_tailroom(b, size);
p = dp_packet_tail(b);
dp_packet_set_size(b, dp_packet_size(b) + size);
return p;
}
/* Called on a sorted complete list of v6 fragments to reassemble them into
* a single packet that can be processed, such as passing through conntrack.
*/
static struct dp_packet *
ipf_reassemble_v6_frags(struct ipf_list *ipf_list)
/* OVS_REQUIRES(ipf_lock) */
{
struct ipf_frag *frag_list = ipf_list->frag_list;
struct dp_packet *pkt = dp_packet_clone(frag_list[0].pkt);
dp_packet_set_size(pkt, dp_packet_size(pkt) - dp_packet_l2_pad_size(pkt));
struct ovs_16aligned_ip6_hdr *l3 = dp_packet_l3(pkt);
int pl = ntohs(l3->ip6_plen) - sizeof(struct ovs_16aligned_ip6_frag);
int rest_len = frag_list[ipf_list->last_inuse_idx].end_data_byte -
frag_list[1].start_data_byte + 1;
if (pl + rest_len > IPV6_PACKET_MAX_DATA) {
ipf_print_reass_packet(
"Unsupported big reassembled v6 packet; v6 hdr:", l3);
dp_packet_delete(pkt);
return NULL;
}
dp_packet_prealloc_tailroom(pkt, rest_len);
for (int i = 1; i <= ipf_list->last_inuse_idx; i++) {
size_t add_len = frag_list[i].end_data_byte -
frag_list[i].start_data_byte + 1;
const char *l4 = dp_packet_l4(frag_list[i].pkt);
dp_packet_put(pkt, l4, add_len);
}
pl += rest_len;
l3 = dp_packet_l3(pkt);
uint8_t nw_proto = l3->ip6_nxt;
uint8_t nw_frag = 0;
const void *data = l3 + 1;
size_t datasize = pl;
const struct ovs_16aligned_ip6_frag *frag_hdr = NULL;
if (!parse_ipv6_ext_hdrs(&data, &datasize, &nw_proto, &nw_frag, &frag_hdr)
|| !nw_frag || !frag_hdr) {
ipf_print_reass_packet("Unparsed reassembled v6 packet; v6 hdr:", l3);
dp_packet_delete(pkt);
return NULL;
}
struct ovs_16aligned_ip6_frag *fh =
CONST_CAST(struct ovs_16aligned_ip6_frag *, frag_hdr);
fh->ip6f_offlg = 0;
l3->ip6_plen = htons(pl);
l3->ip6_ctlun.ip6_un1.ip6_un1_nxt = nw_proto;
dp_packet_set_l2_pad_size(pkt, 0);
return pkt;
}
/* Called on a sorted complete list of v4 fragments to reassemble them into
* a single packet that can be processed, such as passing through conntrack.
*/
static struct dp_packet *
ipf_reassemble_v4_frags(struct ipf_list *ipf_list)
/* OVS_REQUIRES(ipf_lock) */
{
struct ipf_frag *frag_list = ipf_list->frag_list;
struct dp_packet *pkt = dp_packet_clone(frag_list[0].pkt);
dp_packet_set_size(pkt, dp_packet_size(pkt) - dp_packet_l2_pad_size(pkt));
struct ip_header *l3 = dp_packet_l3(pkt);
int len = ntohs(l3->ip_tot_len);
int rest_len = frag_list[ipf_list->last_inuse_idx].end_data_byte -
frag_list[1].start_data_byte + 1;
if (len + rest_len > IPV4_PACKET_MAX_SIZE) {
ipf_print_reass_packet(
"Unsupported big reassembled v4 packet; v4 hdr:", l3);
dp_packet_delete(pkt);
return NULL;
}
dp_packet_prealloc_tailroom(pkt, rest_len);
for (int i = 1; i <= ipf_list->last_inuse_idx; i++) {
size_t add_len = frag_list[i].end_data_byte -
frag_list[i].start_data_byte + 1;
const char *l4 = dp_packet_l4(frag_list[i].pkt);
dp_packet_put(pkt, l4, add_len);
}
len += rest_len;
l3 = dp_packet_l3(pkt);
ovs_be16 new_ip_frag_off = l3->ip_frag_off & ~htons(IP_MORE_FRAGMENTS);
l3->ip_csum = recalc_csum16(l3->ip_csum, l3->ip_frag_off,
new_ip_frag_off);
l3->ip_csum = recalc_csum16(l3->ip_csum, l3->ip_tot_len, htons(len));
l3->ip_tot_len = htons(len);
l3->ip_frag_off = new_ip_frag_off;
dp_packet_set_l2_pad_size(pkt, 0);
return pkt;
}
