packet: support extensible, 64 bit clean mmaped ring structure
The tpacket_hdr is not 64 bit clean due to use of an unsigned long
and can't be extended because the following struct sockaddr_ll needs
to be at a fixed offset.
Add support for a version 2 tpacket protocol that removes these
limitations.
Userspace can query the header size through a new getsockopt option
and change the protocol version through a setsockopt option. The
changes needed to switch to the new protocol version are:
1. replace struct tpacket_hdr by struct tpacket2_hdr
2. query header len and save
3. set protocol version to 2
- set up ring as usual
4. for getting the sockaddr_ll, use (void *)hdr + TPACKET_ALIGN(hdrlen)
instead of (void *)hdr + TPACKET_ALIGN(sizeof(struct tpacket_hdr))
Steps 2 and 4 can be omitted if the struct sockaddr_ll isn't needed.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 9f22691..4f05977 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -186,6 +186,8 @@
unsigned int pg_vec_order;
unsigned int pg_vec_pages;
unsigned int pg_vec_len;
+ enum tpacket_versions tp_version;
+ unsigned int tp_hdrlen;
#endif
};
@@ -201,14 +203,52 @@
#ifdef CONFIG_PACKET_MMAP
-static inline struct tpacket_hdr *packet_lookup_frame(struct packet_sock *po, unsigned int position)
+static void *packet_lookup_frame(struct packet_sock *po, 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 / po->frames_per_block;
frame_offset = position % po->frames_per_block;
- return (struct tpacket_hdr *)(po->pg_vec[pg_vec_pos] + (frame_offset * po->frame_size));
+ h.raw = po->pg_vec[pg_vec_pos] + (frame_offset * po->frame_size);
+ switch (po->tp_version) {
+ case TPACKET_V1:
+ if (status != h.h1->tp_status ? TP_STATUS_USER :
+ TP_STATUS_KERNEL)
+ return NULL;
+ break;
+ case TPACKET_V2:
+ if (status != h.h2->tp_status ? TP_STATUS_USER :
+ TP_STATUS_KERNEL)
+ return NULL;
+ break;
+ }
+ return h.raw;
+}
+
+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;
+ break;
+ case TPACKET_V2:
+ h.h2->tp_status = status;
+ break;
+ }
}
#endif
@@ -551,14 +591,19 @@
struct sock *sk;
struct packet_sock *po;
struct sockaddr_ll *sll;
- struct tpacket_hdr *h;
+ 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;
+ unsigned short macoff, netoff, hdrlen;
struct sk_buff *copy_skb = NULL;
struct timeval tv;
+ struct timespec ts;
if (skb->pkt_type == PACKET_LOOPBACK)
goto drop;
@@ -590,10 +635,11 @@
snaplen = res;
if (sk->sk_type == SOCK_DGRAM) {
- macoff = netoff = TPACKET_ALIGN(TPACKET_HDRLEN) + 16;
+ macoff = netoff = TPACKET_ALIGN(po->tp_hdrlen) + 16;
} else {
unsigned maclen = skb_network_offset(skb);
- netoff = TPACKET_ALIGN(TPACKET_HDRLEN + (maclen < 16 ? 16 : maclen));
+ netoff = TPACKET_ALIGN(po->tp_hdrlen +
+ (maclen < 16 ? 16 : maclen));
macoff = netoff - maclen;
}
@@ -616,9 +662,8 @@
}
spin_lock(&sk->sk_receive_queue.lock);
- h = packet_lookup_frame(po, po->head);
-
- if (h->tp_status)
+ h.raw = packet_lookup_frame(po, po->head, TP_STATUS_KERNEL);
+ if (!h.raw)
goto ring_is_full;
po->head = po->head != po->frame_max ? po->head+1 : 0;
po->stats.tp_packets++;
@@ -630,20 +675,40 @@
status &= ~TP_STATUS_LOSING;
spin_unlock(&sk->sk_receive_queue.lock);
- skb_copy_bits(skb, 0, (u8*)h + macoff, snaplen);
+ skb_copy_bits(skb, 0, h.raw + macoff, snaplen);
- h->tp_len = skb->len;
- h->tp_snaplen = snaplen;
- h->tp_mac = macoff;
- h->tp_net = netoff;
- if (skb->tstamp.tv64)
- tv = ktime_to_timeval(skb->tstamp);
- else
- do_gettimeofday(&tv);
- h->tp_sec = tv.tv_sec;
- h->tp_usec = tv.tv_usec;
+ 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 (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 (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;
+ hdrlen = sizeof(*h.h2);
+ break;
+ default:
+ BUG();
+ }
- sll = (struct sockaddr_ll*)((u8*)h + TPACKET_ALIGN(sizeof(*h)));
+ 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;
@@ -654,14 +719,14 @@
else
sll->sll_ifindex = dev->ifindex;
- h->tp_status = status;
+ __packet_set_status(po, h.raw, status);
smp_mb();
{
struct page *p_start, *p_end;
- u8 *h_end = (u8 *)h + macoff + snaplen - 1;
+ u8 *h_end = h.raw + macoff + snaplen - 1;
- p_start = virt_to_page(h);
+ p_start = virt_to_page(h.raw);
p_end = virt_to_page(h_end);
while (p_start <= p_end) {
flush_dcache_page(p_start);
@@ -1362,6 +1427,25 @@
pkt_sk(sk)->copy_thresh = val;
return 0;
}
+ case PACKET_VERSION:
+ {
+ int val;
+
+ if (optlen != sizeof(val))
+ return -EINVAL;
+ if (po->pg_vec)
+ return -EBUSY;
+ if (copy_from_user(&val, optval, sizeof(val)))
+ return -EFAULT;
+ switch (val) {
+ case TPACKET_V1:
+ case TPACKET_V2:
+ po->tp_version = val;
+ return 0;
+ default:
+ return -EINVAL;
+ }
+ }
#endif
case PACKET_AUXDATA:
{
@@ -1437,6 +1521,31 @@
data = &val;
break;
+#ifdef CONFIG_PACKET_MMAP
+ case PACKET_VERSION:
+ if (len > sizeof(int))
+ len = sizeof(int);
+ val = po->tp_version;
+ data = &val;
+ break;
+ case PACKET_HDRLEN:
+ if (len > sizeof(int))
+ len = sizeof(int);
+ if (copy_from_user(&val, optval, len))
+ return -EFAULT;
+ switch (val) {
+ case TPACKET_V1:
+ val = sizeof(struct tpacket_hdr);
+ break;
+ case TPACKET_V2:
+ val = sizeof(struct tpacket2_hdr);
+ break;
+ default:
+ return -EINVAL;
+ }
+ data = &val;
+ break;
+#endif
default:
return -ENOPROTOOPT;
}
@@ -1570,11 +1679,8 @@
spin_lock_bh(&sk->sk_receive_queue.lock);
if (po->pg_vec) {
unsigned last = po->head ? po->head-1 : po->frame_max;
- struct tpacket_hdr *h;
- h = packet_lookup_frame(po, last);
-
- if (h->tp_status)
+ if (packet_lookup_frame(po, last, TP_STATUS_USER))
mask |= POLLIN | POLLRDNORM;
}
spin_unlock_bh(&sk->sk_receive_queue.lock);
@@ -1669,11 +1775,20 @@
if (unlikely(po->pg_vec))
return -EBUSY;
+ switch (po->tp_version) {
+ case TPACKET_V1:
+ po->tp_hdrlen = TPACKET_HDRLEN;
+ break;
+ case TPACKET_V2:
+ po->tp_hdrlen = TPACKET2_HDRLEN;
+ break;
+ }
+
if (unlikely((int)req->tp_block_size <= 0))
return -EINVAL;
if (unlikely(req->tp_block_size & (PAGE_SIZE - 1)))
return -EINVAL;
- if (unlikely(req->tp_frame_size < TPACKET_HDRLEN))
+ if (unlikely(req->tp_frame_size < po->tp_hdrlen))
return -EINVAL;
if (unlikely(req->tp_frame_size & (TPACKET_ALIGNMENT - 1)))
return -EINVAL;
@@ -1692,13 +1807,11 @@
goto out;
for (i = 0; i < req->tp_block_nr; i++) {
- char *ptr = pg_vec[i];
- struct tpacket_hdr *header;
+ void *ptr = pg_vec[i];
int k;
for (k = 0; k < po->frames_per_block; k++) {
- header = (struct tpacket_hdr *) ptr;
- header->tp_status = TP_STATUS_KERNEL;
+ __packet_set_status(po, ptr, TP_STATUS_KERNEL);
ptr += req->tp_frame_size;
}
}