netpoll: factor out UDP header setup into push_udp() helper

Move UDP header construction from netpoll_send_udp() into a new
static helper function push_udp(). This completes the protocol
layer refactoring by:

1. Creating a dedicated helper for UDP header assembly
2. Removing UDP-specific logic from the main send function
3. Establishing a consistent pattern with existing IPv4/IPv6 helpers:
   - push_udp()
   - push_ipv4()
   - push_ipv6()

The change improves code organization and maintains the encapsulation
pattern established in previous refactorings.

Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250702-netpoll_untagle_ip-v2-5-13cf3db24e2b@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index ff64e94df5351568953289f8ca6e850758ba195f..70035e27d91cc7ccfd24088211be3266bf33e146 100644 (file)
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -473,11 +473,28 @@ static void push_ipv4(struct netpoll *np, struct sk_buff *skb, int len)
        eth->h_proto = htons(ETH_P_IP);
 }
 
+static void push_udp(struct netpoll *np, struct sk_buff *skb, int len)
+{
+       struct udphdr *udph;
+       int udp_len;
+
+       udp_len = len + sizeof(struct udphdr);
+
+       skb_push(skb, sizeof(struct udphdr));
+       skb_reset_transport_header(skb);
+
+       udph = udp_hdr(skb);
+       udph->source = htons(np->local_port);
+       udph->dest = htons(np->remote_port);
+       udph->len = htons(udp_len);
+
+       netpoll_udp_checksum(np, skb, len);
+}
+
 int netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 {
        int total_len, ip_len, udp_len;
        struct sk_buff *skb;
-       struct udphdr *udph;
        struct ethhdr *eth;
 
        if (!IS_ENABLED(CONFIG_PREEMPT_RT))
@@ -499,14 +516,7 @@ int netpoll_send_udp(struct netpoll *np, const char *msg, int len)
        skb_copy_to_linear_data(skb, msg, len);
        skb_put(skb, len);
 
-       skb_push(skb, sizeof(struct udphdr));
-       skb_reset_transport_header(skb);
-       udph = udp_hdr(skb);
-       udph->source = htons(np->local_port);
-       udph->dest = htons(np->remote_port);
-       udph->len = htons(udp_len);
-
-       netpoll_udp_checksum(np, skb, len);
+       push_udp(np, skb, len);
        if (np->ipv6)
                push_ipv6(np, skb, len);
        else