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af_packet.c
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/*
* 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.
*
* PACKET - implements raw packet sockets.
*
* Authors: Ross Biro
* Fred N. van Kempen, <[email protected]>
* Alan Cox, <[email protected]>
*
* Fixes:
* Alan Cox : verify_area() now used correctly
* Alan Cox : new skbuff lists, look ma no backlogs!
* Alan Cox : tidied skbuff lists.
* Alan Cox : Now uses generic datagram routines I
* added. Also fixed the peek/read crash
* from all old Linux datagram code.
* Alan Cox : Uses the improved datagram code.
* Alan Cox : Added NULL's for socket options.
* Alan Cox : Re-commented the code.
* Alan Cox : Use new kernel side addressing
* Rob Janssen : Correct MTU usage.
* Dave Platt : Counter leaks caused by incorrect
* interrupt locking and some slightly
* dubious gcc output. Can you read
* compiler: it said _VOLATILE_
* Richard Kooijman : Timestamp fixes.
* Alan Cox : New buffers. Use sk->mac.raw.
* Alan Cox : sendmsg/recvmsg support.
* Alan Cox : Protocol setting support
* Alexey Kuznetsov : Untied from IPv4 stack.
* Cyrus Durgin : Fixed kerneld for kmod.
* Michal Ostrowski : Module initialization cleanup.
* Ulises Alonso : Frame number limit removal and
* packet_set_ring memory leak.
* Eric Biederman : Allow for > 8 byte hardware addresses.
* The convention is that longer addresses
* will simply extend the hardware address
* byte arrays at the end of sockaddr_ll
* and packet_mreq.
* Johann Baudy : Added TX RING.
*
* 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/types.h>
#include <linux/mm.h>
#include <linux/capability.h>
#include <linux/fcntl.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/if_packet.h>
#include <linux/wireless.h>
#include <linux/kernel.h>
#include <linux/kmod.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <net/net_namespace.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/ioctls.h>
#include <asm/page.h>
#include <asm/cacheflush.h>
#include <asm/io.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/poll.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/if_vlan.h>
#include <linux/virtio_net.h>
#include <linux/errqueue.h>
#include <linux/net_tstamp.h>
#ifdef CONFIG_INET
#include <net/inet_common.h>
#endif
/*
Assumptions:
- if device has no dev->hard_header routine, it adds and removes ll header
inside itself. In this case ll header is invisible outside of device,
but higher levels still should reserve dev->hard_header_len.
Some devices are enough clever to reallocate skb, when header
will not fit to reserved space (tunnel), another ones are silly
(PPP).
- packet socket receives packets with pulled ll header,
so that SOCK_RAW should push it back.
On receive:
-----------
Incoming, dev->hard_header!=NULL
mac_header -> ll header
data -> data
Outgoing, dev->hard_header!=NULL
mac_header -> ll header
data -> ll header
Incoming, dev->hard_header==NULL
mac_header -> UNKNOWN position. It is very likely, that it points to ll
header. PPP makes it, that is wrong, because introduce
assymetry between rx and tx paths.
data -> data
Outgoing, dev->hard_header==NULL
mac_header -> data. ll header is still not built!
data -> data
Resume
If dev->hard_header==NULL we are unlikely to restore sensible ll header.
On transmit:
------------
dev->hard_header != NULL
mac_header -> ll header
data -> ll header
dev->hard_header == NULL (ll header is added by device, we cannot control it)
mac_header -> data
data -> data
We should set nh.raw on output to correct posistion,
packet classifier depends on it.
*/
/* Private packet socket structures. */
struct packet_mclist {
struct packet_mclist *next;
int ifindex;
int count;
unsigned short type;
unsigned short alen;
unsigned char addr[MAX_ADDR_LEN];
};
/* identical to struct packet_mreq except it has
* a longer address field.
*/
struct packet_mreq_max {
int mr_ifindex;
unsigned short mr_type;
unsigned short mr_alen;
unsigned char mr_address[MAX_ADDR_LEN];
};
static int packet_set_ring(struct sock *sk, struct tpacket_req *req,
int closing, int tx_ring);
struct pgv {
char *buffer;
};
struct packet_ring_buffer {
struct pgv *pg_vec;
unsigned int head;
unsigned int frames_per_block;
unsigned int frame_size;
unsigned int frame_max;
unsigned int pg_vec_order;
unsigned int pg_vec_pages;
unsigned int pg_vec_len;
atomic_t pending;
};
struct packet_sock;
static int tpacket_snd(struct packet_sock *po, struct msghdr *msg);
static void packet_flush_mclist(struct sock *sk);
struct packet_sock {
/* struct sock has to be the first member of packet_sock */
struct sock sk;
struct tpacket_stats stats;
struct packet_ring_buffer rx_ring;
struct packet_ring_buffer tx_ring;
int copy_thresh;
spinlock_t bind_lock;
struct mutex pg_vec_lock;
unsigned int running:1, /* prot_hook is attached*/
auxdata:1,
origdev:1,
has_vnet_hdr:1;
int ifindex; /* bound device */
__be16 num;
struct packet_mclist *mclist;
atomic_t mapped;
enum tpacket_versions tp_version;
unsigned int tp_hdrlen;
unsigned int tp_reserve;
unsigned int tp_loss:1;
unsigned int tp_tstamp;
struct packet_type prot_hook ____cacheline_aligned_in_smp;
};
struct packet_skb_cb {
unsigned int origlen;
union {
struct sockaddr_pkt pkt;
struct sockaddr_ll ll;
} sa;
};
#define PACKET_SKB_CB(__skb) ((struct packet_skb_cb *)((__skb)->cb))
static inline __pure struct page *pgv_to_page(void *addr)
{
if (is_vmalloc_addr(addr))
return vmalloc_to_page(addr);
return virt_to_page(addr);
}
static void __packet_set_status(struct packet_sock *po, void *frame, int status)
{
union {
struct tpacket_hdr *h1;
struct tpacket2_hdr *h2;
void *raw;
} h;
h.raw = frame;
switch (po->tp_version) {
case TPACKET_V1:
h.h1->tp_status = status;
flush_dcache_page(pgv_to_page(&h.h1->tp_status));
break;
case TPACKET_V2:
h.h2->tp_status = status;
flush_dcache_page(pgv_to_page(&h.h2->tp_status));
break;
default:
pr_err("TPACKET version not supported\n");
BUG();
}
smp_wmb();
}
static int __packet_get_status(struct packet_sock *po, void *frame)
{
union {
struct tpacket_hdr *h1;
struct tpacket2_hdr *h2;
void *raw;
} h;
smp_rmb();
h.raw = frame;
switch (po->tp_version) {
case TPACKET_V1:
flush_dcache_page(pgv_to_page(&h.h1->tp_status));
return h.h1->tp_status;
case TPACKET_V2:
flush_dcache_page(pgv_to_page(&h.h2->tp_status));
return h.h2->tp_status;
default:
pr_err("TPACKET version not supported\n");
BUG();
return 0;
}
}
static void *packet_lookup_frame(struct packet_sock *po,
struct packet_ring_buffer *rb,
unsigned int position,
int status)
{
unsigned int pg_vec_pos, frame_offset;
union {
struct tpacket_hdr *h1;
struct tpacket2_hdr *h2;
void *raw;
} h;
pg_vec_pos = position / rb->frames_per_block;
frame_offset = position % rb->frames_per_block;
h.raw = rb->pg_vec[pg_vec_pos].buffer +
(frame_offset * rb->frame_size);
if (status != __packet_get_status(po, h.raw))
return NULL;
return h.raw;
}
static inline void *packet_current_frame(struct packet_sock *po,
struct packet_ring_buffer *rb,
int status)
{
return packet_lookup_frame(po, rb, rb->head, status);
}
static inline void *packet_previous_frame(struct packet_sock *po,
struct packet_ring_buffer *rb,
int status)
{
unsigned int previous = rb->head ? rb->head - 1 : rb->frame_max;
return packet_lookup_frame(po, rb, previous, status);
}
static inline void packet_increment_head(struct packet_ring_buffer *buff)
{
buff->head = buff->head != buff->frame_max ? buff->head+1 : 0;
}
static inline struct packet_sock *pkt_sk(struct sock *sk)
{
return (struct packet_sock *)sk;
}
static void packet_sock_destruct(struct sock *sk)
{
skb_queue_purge(&sk->sk_error_queue);
WARN_ON(atomic_read(&sk->sk_rmem_alloc));
WARN_ON(atomic_read(&sk->sk_wmem_alloc));
if (!sock_flag(sk, SOCK_DEAD)) {
pr_err("Attempt to release alive packet socket: %p\n", sk);
return;
}
sk_refcnt_debug_dec(sk);
}
static const struct proto_ops packet_ops;
static const struct proto_ops packet_ops_spkt;
static int packet_rcv_spkt(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt, struct net_device *orig_dev)
{
struct sock *sk;
struct sockaddr_pkt *spkt;
/*
* When we registered the protocol we saved the socket in the data
* field for just this event.
*/
sk = pt->af_packet_priv;
/*
* Yank back the headers [hope the device set this
* right or kerboom...]
*
* Incoming packets have ll header pulled,
* push it back.
*
* For outgoing ones skb->data == skb_mac_header(skb)
* so that this procedure is noop.
*/
if (skb->pkt_type == PACKET_LOOPBACK)
goto out;
if (!net_eq(dev_net(dev), sock_net(sk)))
goto out;
skb = skb_share_check(skb, GFP_ATOMIC);
if (skb == NULL)
goto oom;
/* drop any routing info */
skb_dst_drop(skb);
/* drop conntrack reference */
nf_reset(skb);
spkt = &PACKET_SKB_CB(skb)->sa.pkt;
skb_push(skb, skb->data - skb_mac_header(skb));
/*
* The SOCK_PACKET socket receives _all_ frames.
*/
spkt->spkt_family = dev->type;
strlcpy(spkt->spkt_device, dev->name, sizeof(spkt->spkt_device));
spkt->spkt_protocol = skb->protocol;
/*
* Charge the memory to the socket. This is done specifically
* to prevent sockets using all the memory up.
*/
if (sock_queue_rcv_skb(sk, skb) == 0)
return 0;
out:
kfree_skb(skb);
oom:
return 0;
}
/*
* Output a raw packet to a device layer. This bypasses all the other
* protocol layers and you must therefore supply it with a complete frame
*/
static int packet_sendmsg_spkt(struct kiocb *iocb, struct socket *sock,
struct msghdr *msg, size_t len)
{
struct sock *sk = sock->sk;
struct sockaddr_pkt *saddr = (struct sockaddr_pkt *)msg->msg_name;
struct sk_buff *skb = NULL;
struct net_device *dev;
__be16 proto = 0;
int err;
/*
* Get and verify the address.
*/
if (saddr) {
if (msg->msg_namelen < sizeof(struct sockaddr))
return -EINVAL;
if (msg->msg_namelen == sizeof(struct sockaddr_pkt))
proto = saddr->spkt_protocol;
} else
return -ENOTCONN; /* SOCK_PACKET must be sent giving an address */
/*
* Find the device first to size check it
*/
saddr->spkt_device[13] = 0;
retry:
rcu_read_lock();
dev = dev_get_by_name_rcu(sock_net(sk), saddr->spkt_device);
err = -ENODEV;
if (dev == NULL)
goto out_unlock;
err = -ENETDOWN;
if (!(dev->flags & IFF_UP))
goto out_unlock;
/*
* You may not queue a frame bigger than the mtu. This is the lowest level
* raw protocol and you must do your own fragmentation at this level.
*/
err = -EMSGSIZE;
if (len > dev->mtu + dev->hard_header_len + VLAN_HLEN)
goto out_unlock;
if (!skb) {
size_t reserved = LL_RESERVED_SPACE(dev);
unsigned int hhlen = dev->header_ops ? dev->hard_header_len : 0;
rcu_read_unlock();
skb = sock_wmalloc(sk, len + reserved, 0, GFP_KERNEL);
if (skb == NULL)
return -ENOBUFS;
/* FIXME: Save some space for broken drivers that write a hard
* header at transmission time by themselves. PPP is the notable
* one here. This should really be fixed at the driver level.
*/
skb_reserve(skb, reserved);
skb_reset_network_header(skb);
/* Try to align data part correctly */
if (hhlen) {
skb->data -= hhlen;
skb->tail -= hhlen;
if (len < hhlen)
skb_reset_network_header(skb);
}
err = memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len);
if (err)
goto out_free;
goto retry;
}
if (len > (dev->mtu + dev->hard_header_len)) {
/* Earlier code assumed this would be a VLAN pkt,
* double-check this now that we have the actual
* packet in hand.
*/
struct ethhdr *ehdr;
skb_reset_mac_header(skb);
ehdr = eth_hdr(skb);
if (ehdr->h_proto != htons(ETH_P_8021Q)) {
err = -EMSGSIZE;
goto out_unlock;
}
}
skb->protocol = proto;
skb->dev = dev;
skb->priority = sk->sk_priority;
skb->mark = sk->sk_mark;
err = sock_tx_timestamp(sk, &skb_shinfo(skb)->tx_flags);
if (err < 0)
goto out_unlock;
dev_queue_xmit(skb);
rcu_read_unlock();
return len;
out_unlock:
rcu_read_unlock();
out_free:
kfree_skb(skb);
return err;
}
static inline unsigned int run_filter(const struct sk_buff *skb,
const struct sock *sk,
unsigned int res)
{
struct sk_filter *filter;
rcu_read_lock();
filter = rcu_dereference(sk->sk_filter);
if (filter != NULL)
res = SK_RUN_FILTER(filter, skb);
rcu_read_unlock();
return res;
}
/*
* This function makes lazy skb cloning in hope that most of packets
* are discarded by BPF.
*
* Note tricky part: we DO mangle shared skb! skb->data, skb->len
* and skb->cb are mangled. It works because (and until) packets
* falling here are owned by current CPU. Output packets are cloned
* by dev_queue_xmit_nit(), input packets are processed by net_bh
* sequencially, so that if we return skb to original state on exit,
* we will not harm anyone.
*/
static int packet_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt, struct net_device *orig_dev)
{
struct sock *sk;
struct sockaddr_ll *sll;
struct packet_sock *po;
u8 *skb_head = skb->data;
int skb_len = skb->len;
unsigned int snaplen, res;
if (skb->pkt_type == PACKET_LOOPBACK)
goto drop;
sk = pt->af_packet_priv;
po = pkt_sk(sk);
if (!net_eq(dev_net(dev), sock_net(sk)))
goto drop;
skb->dev = dev;
if (dev->header_ops) {
/* The device has an explicit notion of ll header,
* exported to higher levels.
*
* Otherwise, the device hides details of its frame
* structure, so that corresponding packet head is
* never delivered to user.
*/
if (sk->sk_type != SOCK_DGRAM)
skb_push(skb, skb->data - skb_mac_header(skb));
else if (skb->pkt_type == PACKET_OUTGOING) {
/* Special case: outgoing packets have ll header at head */
skb_pull(skb, skb_network_offset(skb));
}
}
snaplen = skb->len;
res = run_filter(skb, sk, snaplen);
if (!res)
goto drop_n_restore;
if (snaplen > res)
snaplen = res;
if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
(unsigned)sk->sk_rcvbuf)
goto drop_n_acct;
if (skb_shared(skb)) {
struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);
if (nskb == NULL)
goto drop_n_acct;
if (skb_head != skb->data) {
skb->data = skb_head;
skb->len = skb_len;
}
kfree_skb(skb);
skb = nskb;
}
BUILD_BUG_ON(sizeof(*PACKET_SKB_CB(skb)) + MAX_ADDR_LEN - 8 >
sizeof(skb->cb));
sll = &PACKET_SKB_CB(skb)->sa.ll;
sll->sll_family = AF_PACKET;
sll->sll_hatype = dev->type;
sll->sll_protocol = skb->protocol;
sll->sll_pkttype = skb->pkt_type;
if (unlikely(po->origdev))
sll->sll_ifindex = orig_dev->ifindex;
else
sll->sll_ifindex = dev->ifindex;
sll->sll_halen = dev_parse_header(skb, sll->sll_addr);
PACKET_SKB_CB(skb)->origlen = skb->len;
if (pskb_trim(skb, snaplen))
goto drop_n_acct;
skb_set_owner_r(skb, sk);
skb->dev = NULL;
skb_dst_drop(skb);
/* drop conntrack reference */
nf_reset(skb);
spin_lock(&sk->sk_receive_queue.lock);
po->stats.tp_packets++;
skb->dropcount = atomic_read(&sk->sk_drops);
__skb_queue_tail(&sk->sk_receive_queue, skb);
spin_unlock(&sk->sk_receive_queue.lock);
sk->sk_data_ready(sk, skb->len);
return 0;
drop_n_acct:
po->stats.tp_drops = atomic_inc_return(&sk->sk_drops);
drop_n_restore:
if (skb_head != skb->data && skb_shared(skb)) {
skb->data = skb_head;
skb->len = skb_len;
}
drop:
consume_skb(skb);
return 0;
}
static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt, struct net_device *orig_dev)
{
struct sock *sk;
struct packet_sock *po;
struct sockaddr_ll *sll;
union {
struct tpacket_hdr *h1;
struct tpacket2_hdr *h2;
void *raw;
} h;
u8 *skb_head = skb->data;
int skb_len = skb->len;
unsigned int snaplen, res;
unsigned long status = TP_STATUS_LOSING|TP_STATUS_USER;
unsigned short macoff, netoff, hdrlen;
struct sk_buff *copy_skb = NULL;
struct timeval tv;
struct timespec ts;
struct skb_shared_hwtstamps *shhwtstamps = skb_hwtstamps(skb);
if (skb->pkt_type == PACKET_LOOPBACK)
goto drop;
sk = pt->af_packet_priv;
po = pkt_sk(sk);
if (!net_eq(dev_net(dev), sock_net(sk)))
goto drop;
if (dev->header_ops) {
if (sk->sk_type != SOCK_DGRAM)
skb_push(skb, skb->data - skb_mac_header(skb));
else if (skb->pkt_type == PACKET_OUTGOING) {
/* Special case: outgoing packets have ll header at head */
skb_pull(skb, skb_network_offset(skb));
}
}
if (skb->ip_summed == CHECKSUM_PARTIAL)
status |= TP_STATUS_CSUMNOTREADY;
snaplen = skb->len;
res = run_filter(skb, sk, snaplen);
if (!res)
goto drop_n_restore;
if (snaplen > res)
snaplen = res;
if (sk->sk_type == SOCK_DGRAM) {
macoff = netoff = TPACKET_ALIGN(po->tp_hdrlen) + 16 +
po->tp_reserve;
} else {
unsigned maclen = skb_network_offset(skb);
netoff = TPACKET_ALIGN(po->tp_hdrlen +
(maclen < 16 ? 16 : maclen)) +
po->tp_reserve;
macoff = netoff - maclen;
}
if (macoff + snaplen > po->rx_ring.frame_size) {
if (po->copy_thresh &&
atomic_read(&sk->sk_rmem_alloc) + skb->truesize <
(unsigned)sk->sk_rcvbuf) {
if (skb_shared(skb)) {
copy_skb = skb_clone(skb, GFP_ATOMIC);
} else {
copy_skb = skb_get(skb);
skb_head = skb->data;
}
if (copy_skb)
skb_set_owner_r(copy_skb, sk);
}
snaplen = po->rx_ring.frame_size - macoff;
if ((int)snaplen < 0)
snaplen = 0;
}
spin_lock(&sk->sk_receive_queue.lock);
h.raw = packet_current_frame(po, &po->rx_ring, TP_STATUS_KERNEL);
if (!h.raw)
goto ring_is_full;
packet_increment_head(&po->rx_ring);
po->stats.tp_packets++;
if (copy_skb) {
status |= TP_STATUS_COPY;
__skb_queue_tail(&sk->sk_receive_queue, copy_skb);
}
if (!po->stats.tp_drops)
status &= ~TP_STATUS_LOSING;
spin_unlock(&sk->sk_receive_queue.lock);
skb_copy_bits(skb, 0, h.raw + macoff, snaplen);
switch (po->tp_version) {
case TPACKET_V1:
h.h1->tp_len = skb->len;
h.h1->tp_snaplen = snaplen;
h.h1->tp_mac = macoff;
h.h1->tp_net = netoff;
if ((po->tp_tstamp & SOF_TIMESTAMPING_SYS_HARDWARE)
&& shhwtstamps->syststamp.tv64)
tv = ktime_to_timeval(shhwtstamps->syststamp);
else if ((po->tp_tstamp & SOF_TIMESTAMPING_RAW_HARDWARE)
&& shhwtstamps->hwtstamp.tv64)
tv = ktime_to_timeval(shhwtstamps->hwtstamp);
else if (skb->tstamp.tv64)
tv = ktime_to_timeval(skb->tstamp);
else
do_gettimeofday(&tv);
h.h1->tp_sec = tv.tv_sec;
h.h1->tp_usec = tv.tv_usec;
hdrlen = sizeof(*h.h1);
break;
case TPACKET_V2:
h.h2->tp_len = skb->len;
h.h2->tp_snaplen = snaplen;
h.h2->tp_mac = macoff;
h.h2->tp_net = netoff;
if ((po->tp_tstamp & SOF_TIMESTAMPING_SYS_HARDWARE)
&& shhwtstamps->syststamp.tv64)
ts = ktime_to_timespec(shhwtstamps->syststamp);
else if ((po->tp_tstamp & SOF_TIMESTAMPING_RAW_HARDWARE)
&& shhwtstamps->hwtstamp.tv64)
ts = ktime_to_timespec(shhwtstamps->hwtstamp);
else if (skb->tstamp.tv64)
ts = ktime_to_timespec(skb->tstamp);
else
getnstimeofday(&ts);
h.h2->tp_sec = ts.tv_sec;
h.h2->tp_nsec = ts.tv_nsec;
if (vlan_tx_tag_present(skb)) {
h.h2->tp_vlan_tci = vlan_tx_tag_get(skb);
status |= TP_STATUS_VLAN_VALID;
} else {
h.h2->tp_vlan_tci = 0;
}
h.h2->tp_padding = 0;
hdrlen = sizeof(*h.h2);
break;
default:
BUG();
}
sll = h.raw + TPACKET_ALIGN(hdrlen);
sll->sll_halen = dev_parse_header(skb, sll->sll_addr);
sll->sll_family = AF_PACKET;
sll->sll_hatype = dev->type;
sll->sll_protocol = skb->protocol;
sll->sll_pkttype = skb->pkt_type;
if (unlikely(po->origdev))
sll->sll_ifindex = orig_dev->ifindex;
else
sll->sll_ifindex = dev->ifindex;
__packet_set_status(po, h.raw, status);
smp_mb();
#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1
{
u8 *start, *end;
end = (u8 *)PAGE_ALIGN((unsigned long)h.raw + macoff + snaplen);
for (start = h.raw; start < end; start += PAGE_SIZE)
flush_dcache_page(pgv_to_page(start));
}
#endif
sk->sk_data_ready(sk, 0);
drop_n_restore:
if (skb_head != skb->data && skb_shared(skb)) {
skb->data = skb_head;
skb->len = skb_len;
}
drop:
kfree_skb(skb);
return 0;
ring_is_full:
po->stats.tp_drops++;
spin_unlock(&sk->sk_receive_queue.lock);
sk->sk_data_ready(sk, 0);
kfree_skb(copy_skb);
goto drop_n_restore;
}
static void tpacket_destruct_skb(struct sk_buff *skb)
{
struct packet_sock *po = pkt_sk(skb->sk);
void *ph;
BUG_ON(skb == NULL);
if (likely(po->tx_ring.pg_vec)) {
ph = skb_shinfo(skb)->destructor_arg;
BUG_ON(__packet_get_status(po, ph) != TP_STATUS_SENDING);
BUG_ON(atomic_read(&po->tx_ring.pending) == 0);
atomic_dec(&po->tx_ring.pending);
__packet_set_status(po, ph, TP_STATUS_AVAILABLE);
}
sock_wfree(skb);
}
static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb,
void *frame, struct net_device *dev, int size_max,
__be16 proto, unsigned char *addr)
{
union {
struct tpacket_hdr *h1;
struct tpacket2_hdr *h2;
void *raw;
} ph;
int to_write, offset, len, tp_len, nr_frags, len_max;
struct socket *sock = po->sk.sk_socket;
struct page *page;
void *data;
int err;
ph.raw = frame;
skb->protocol = proto;
skb->dev = dev;
skb->priority = po->sk.sk_priority;
skb->mark = po->sk.sk_mark;
skb_shinfo(skb)->destructor_arg = ph.raw;
switch (po->tp_version) {
case TPACKET_V2:
tp_len = ph.h2->tp_len;
break;
default:
tp_len = ph.h1->tp_len;
break;
}
if (unlikely(tp_len > size_max)) {
pr_err("packet size is too long (%d > %d)\n", tp_len, size_max);
return -EMSGSIZE;
}
skb_reserve(skb, LL_RESERVED_SPACE(dev));
skb_reset_network_header(skb);
data = ph.raw + po->tp_hdrlen - sizeof(struct sockaddr_ll);
to_write = tp_len;
if (sock->type == SOCK_DGRAM) {
err = dev_hard_header(skb, dev, ntohs(proto), addr,
NULL, tp_len);
if (unlikely(err < 0))
return -EINVAL;
} else if (dev->hard_header_len) {
/* net device doesn't like empty head */
if (unlikely(tp_len <= dev->hard_header_len)) {
pr_err("packet size is too short (%d < %d)\n",
tp_len, dev->hard_header_len);
return -EINVAL;
}
skb_push(skb, dev->hard_header_len);
err = skb_store_bits(skb, 0, data,
dev->hard_header_len);
if (unlikely(err))
return err;
data += dev->hard_header_len;
to_write -= dev->hard_header_len;
}
err = -EFAULT;
offset = offset_in_page(data);
len_max = PAGE_SIZE - offset;
len = ((to_write > len_max) ? len_max : to_write);
skb->data_len = to_write;
skb->len += to_write;
skb->truesize += to_write;
atomic_add(to_write, &po->sk.sk_wmem_alloc);
while (likely(to_write)) {
nr_frags = skb_shinfo(skb)->nr_frags;
if (unlikely(nr_frags >= MAX_SKB_FRAGS)) {
pr_err("Packet exceed the number of skb frags(%lu)\n",
MAX_SKB_FRAGS);
return -EFAULT;
}
page = pgv_to_page(data);
data += len;
flush_dcache_page(page);
get_page(page);
skb_fill_page_desc(skb, nr_frags, page, offset, len);
to_write -= len;
offset = 0;
len_max = PAGE_SIZE;
len = ((to_write > len_max) ? len_max : to_write);
}
return tp_len;
}
static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
{
struct sk_buff *skb;
struct net_device *dev;
__be16 proto;
int ifindex, err, reserve = 0;
void *ph;
struct sockaddr_ll *saddr = (struct sockaddr_ll *)msg->msg_name;
int tp_len, size_max;
unsigned char *addr;
int len_sum = 0;
int status = 0;
mutex_lock(&po->pg_vec_lock);
err = -EBUSY;
if (saddr == NULL) {
ifindex = po->ifindex;
proto = po->num;
addr = NULL;
} else {
err = -EINVAL;
if (msg->msg_namelen < sizeof(struct sockaddr_ll))
goto out;
if (msg->msg_namelen < (saddr->sll_halen
+ offsetof(struct sockaddr_ll,
sll_addr)))
goto out;