From: Joe Damato <joe@dama.to>
To: netdev@vger.kernel.org,
Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Simon Horman <horms@kernel.org>
Cc: andrew+netdev@lunn.ch, willemb@google.com,
Joe Damato <joe@dama.to>,
linux-kernel@vger.kernel.org
Subject: [PATCH net-next 1/2] net/packet: Reduce VLAN tag code duplication
Date: Tue, 11 Aug 2026 11:47:19 -0700 [thread overview]
Message-ID: <20260811184722.2612345-2-joe@dama.to> (raw)
In-Reply-To: <20260811184722.2612345-1-joe@dama.to>
Reduce code duplication for VLAN tag extraction by factoring the
repeated code into a helper and using it.
Signed-off-by: Joe Damato <joe@dama.to>
---
net/packet/af_packet.c | 95 +++++++++++++++++++++++-------------------
1 file changed, 53 insertions(+), 42 deletions(-)
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 435756877aba..ee60dcc639ad 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -568,6 +568,27 @@ static u16 vlan_get_tci(const struct sk_buff *skb, struct net_device *dev)
return ntohs(vh->h_vlan_TCI);
}
+static bool packet_get_vlan_tci_tpid(const struct sk_buff *skb,
+ struct net_device *dev,
+ u16 *tci, u16 *tpid)
+{
+ if (skb_vlan_tag_present(skb)) {
+ *tci = skb_vlan_tag_get(skb);
+ *tpid = ntohs(skb->vlan_proto);
+ return true;
+ }
+
+ if (unlikely(dev && eth_type_vlan(skb->protocol))) {
+ *tci = vlan_get_tci(skb, dev);
+ *tpid = ntohs(skb->protocol);
+ return true;
+ }
+
+ *tci = 0;
+ *tpid = 0;
+ return false;
+}
+
static __be16 vlan_get_protocol_dgram(const struct sk_buff *skb)
{
__be16 proto = skb->protocol;
@@ -997,20 +1018,19 @@ static void prb_fill_vlan_info(struct tpacket_kbdq_core *pkc,
struct tpacket3_hdr *ppd)
{
struct packet_sock *po = container_of(pkc, struct packet_sock, rx_ring.prb_bdqc);
+ struct net_device *dev = NULL;
+ u16 tci, tpid;
- if (skb_vlan_tag_present(pkc->skb)) {
- ppd->hv1.tp_vlan_tci = skb_vlan_tag_get(pkc->skb);
- ppd->hv1.tp_vlan_tpid = ntohs(pkc->skb->vlan_proto);
- ppd->tp_status = TP_STATUS_VLAN_VALID | TP_STATUS_VLAN_TPID_VALID;
- } else if (unlikely(po->sk.sk_type == SOCK_DGRAM && eth_type_vlan(pkc->skb->protocol))) {
- ppd->hv1.tp_vlan_tci = vlan_get_tci(pkc->skb, pkc->skb->dev);
- ppd->hv1.tp_vlan_tpid = ntohs(pkc->skb->protocol);
+ if (po->sk.sk_type == SOCK_DGRAM)
+ dev = pkc->skb->dev;
+
+ if (packet_get_vlan_tci_tpid(pkc->skb, dev, &tci, &tpid))
ppd->tp_status = TP_STATUS_VLAN_VALID | TP_STATUS_VLAN_TPID_VALID;
- } else {
- ppd->hv1.tp_vlan_tci = 0;
- ppd->hv1.tp_vlan_tpid = 0;
+ else
ppd->tp_status = TP_STATUS_AVAILABLE;
- }
+
+ ppd->hv1.tp_vlan_tci = tci;
+ ppd->hv1.tp_vlan_tpid = tpid;
}
static void prb_run_all_ft_ops(struct tpacket_kbdq_core *pkc,
@@ -2247,6 +2267,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
struct packet_type *pt, struct net_device *orig_dev)
{
enum skb_drop_reason drop_reason = SKB_CONSUMED;
+ struct net_device *vlan_dev = NULL;
struct sock *sk = NULL;
struct packet_sock *po;
struct sockaddr_ll *sll;
@@ -2262,6 +2283,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
__u32 ts_status;
unsigned int slot_id = 0;
int vnet_hdr_sz = 0;
+ u16 tci, tpid;
/* struct tpacket{2,3}_hdr is aligned to a multiple of TPACKET_ALIGNMENT.
* We may add members to them until current aligned size without forcing
@@ -2436,18 +2458,12 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
h.h2->tp_net = netoff;
h.h2->tp_sec = ts.tv_sec;
h.h2->tp_nsec = ts.tv_nsec;
- if (skb_vlan_tag_present(skb)) {
- h.h2->tp_vlan_tci = skb_vlan_tag_get(skb);
- h.h2->tp_vlan_tpid = ntohs(skb->vlan_proto);
- status |= TP_STATUS_VLAN_VALID | TP_STATUS_VLAN_TPID_VALID;
- } else if (unlikely(sk->sk_type == SOCK_DGRAM && eth_type_vlan(skb->protocol))) {
- h.h2->tp_vlan_tci = vlan_get_tci(skb, skb->dev);
- h.h2->tp_vlan_tpid = ntohs(skb->protocol);
+ if (sk->sk_type == SOCK_DGRAM)
+ vlan_dev = skb->dev;
+ if (packet_get_vlan_tci_tpid(skb, vlan_dev, &tci, &tpid))
status |= TP_STATUS_VLAN_VALID | TP_STATUS_VLAN_TPID_VALID;
- } else {
- h.h2->tp_vlan_tci = 0;
- h.h2->tp_vlan_tpid = 0;
- }
+ h.h2->tp_vlan_tci = tci;
+ h.h2->tp_vlan_tpid = tpid;
memset(h.h2->tp_padding, 0, sizeof(h.h2->tp_padding));
hdrlen = sizeof(*h.h2);
break;
@@ -3547,7 +3563,9 @@ static int packet_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
}
if (packet_sock_flag(pkt_sk(sk), PACKET_SOCK_AUXDATA)) {
+ struct net_device *vlan_dev = NULL;
struct tpacket_auxdata aux;
+ u16 tci, tpid;
aux.tp_status = TP_STATUS_USER;
if (skb->ip_summed == CHECKSUM_PARTIAL)
@@ -3562,29 +3580,22 @@ static int packet_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
aux.tp_snaplen = skb->len;
aux.tp_mac = 0;
aux.tp_net = skb_network_offset(skb);
- if (skb_vlan_tag_present(skb)) {
- aux.tp_vlan_tci = skb_vlan_tag_get(skb);
- aux.tp_vlan_tpid = ntohs(skb->vlan_proto);
- aux.tp_status |= TP_STATUS_VLAN_VALID | TP_STATUS_VLAN_TPID_VALID;
- } else if (unlikely(sock->type == SOCK_DGRAM && eth_type_vlan(skb->protocol))) {
+ rcu_read_lock();
+ if (unlikely(sock->type == SOCK_DGRAM &&
+ !skb_vlan_tag_present(skb) &&
+ eth_type_vlan(skb->protocol))) {
struct sockaddr_ll *sll = &PACKET_SKB_CB(skb)->sa.ll;
- struct net_device *dev;
- rcu_read_lock();
- dev = dev_get_by_index_rcu(sock_net(sk), sll->sll_ifindex);
- if (dev) {
- aux.tp_vlan_tci = vlan_get_tci(skb, dev);
- aux.tp_vlan_tpid = ntohs(skb->protocol);
- aux.tp_status |= TP_STATUS_VLAN_VALID | TP_STATUS_VLAN_TPID_VALID;
- } else {
- aux.tp_vlan_tci = 0;
- aux.tp_vlan_tpid = 0;
- }
- rcu_read_unlock();
- } else {
- aux.tp_vlan_tci = 0;
- aux.tp_vlan_tpid = 0;
+ vlan_dev = dev_get_by_index_rcu(sock_net(sk),
+ sll->sll_ifindex);
}
+ if (packet_get_vlan_tci_tpid(skb, vlan_dev, &tci, &tpid))
+ aux.tp_status |= TP_STATUS_VLAN_VALID |
+ TP_STATUS_VLAN_TPID_VALID;
+ rcu_read_unlock();
+
+ aux.tp_vlan_tci = tci;
+ aux.tp_vlan_tpid = tpid;
put_cmsg(msg, SOL_PACKET, PACKET_AUXDATA, sizeof(aux), &aux);
}
--
2.53.0-Meta
next prev parent reply other threads:[~2026-08-11 18:47 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-11 18:47 [PATCH net-next 0/2] packet socket cleanup Joe Damato
2026-08-11 18:47 ` Joe Damato [this message]
2026-08-11 18:47 ` [PATCH net-next 2/2] net/packet: Use copy_safe_from_sockptr to dedupe code Joe Damato
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