Commit 8c27639d authored by Breno Leitao's avatar Breno Leitao Committed by Jakub Kicinski
Browse files

netpoll: factor out IPv4 header setup into push_ipv4() helper 



Move IPv4 header construction from netpoll_send_udp() into a new
static helper function push_ipv4(). This completes the refactoring
started with IPv6 header handling, creating symmetric helper functions
for both IP versions.

Changes include:
1. Extracting IPv4 header setup logic into push_ipv4()
2. Replacing inline IPv4 code with helper call
3. Moving eth assignment after helper calls for consistency

The refactoring reduces code duplication and improves maintainability
by isolating IP version-specific logic.

Signed-off-by: default avatarBreno Leitao <leitao@debian.org>
Reviewed-by: default avatarSimon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250702-netpoll_untagle_ip-v2-4-13cf3db24e2b@debian.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 839388f3

net/core/netpoll.c

+36 −26
Original line number Diff line number Diff line
@@ -441,14 +441,44 @@ static void push_ipv6(struct netpoll *np, struct sk_buff *skb, int len) 
	eth->h_proto = htons(ETH_P_IPV6);

}



static void push_ipv4(struct netpoll *np, struct sk_buff *skb, int len)

{

	static atomic_t ip_ident;

	struct ethhdr *eth;

	struct iphdr *iph;

	int ip_len;



	ip_len = len + sizeof(struct udphdr) + sizeof(struct iphdr);



	skb_push(skb, sizeof(struct iphdr));

	skb_reset_network_header(skb);

	iph = ip_hdr(skb);



	/* iph->version = 4; iph->ihl = 5; */

	*(unsigned char *)iph = 0x45;

	iph->tos = 0;

	put_unaligned(htons(ip_len), &iph->tot_len);

	iph->id = htons(atomic_inc_return(&ip_ident));

	iph->frag_off = 0;

	iph->ttl = 64;

	iph->protocol = IPPROTO_UDP;

	iph->check = 0;

	put_unaligned(np->local_ip.ip, &iph->saddr);

	put_unaligned(np->remote_ip.ip, &iph->daddr);

	iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);



	eth = skb_push(skb, ETH_HLEN);

	skb_reset_mac_header(skb);

	skb->protocol = htons(ETH_P_IP);

	eth->h_proto = htons(ETH_P_IP);

}



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 iphdr *iph;

	struct ethhdr *eth;

	static atomic_t ip_ident;



	if (!IS_ENABLED(CONFIG_PREEMPT_RT))

		WARN_ON_ONCE(!irqs_disabled());
@@ -477,32 +507,12 @@ int netpoll_send_udp(struct netpoll *np, const char *msg, int len) 
	udph->len = htons(udp_len);



	netpoll_udp_checksum(np, skb, len);

	if (np->ipv6) {

	if (np->ipv6)

		push_ipv6(np, skb, len);

		eth = eth_hdr(skb);

	} else {

		skb_push(skb, sizeof(struct iphdr));

		skb_reset_network_header(skb);

		iph = ip_hdr(skb);



		/* iph->version = 4; iph->ihl = 5; */

		*(unsigned char *)iph = 0x45;

		iph->tos      = 0;

		put_unaligned(htons(ip_len), &(iph->tot_len));

		iph->id       = htons(atomic_inc_return(&ip_ident));

		iph->frag_off = 0;

		iph->ttl      = 64;

		iph->protocol = IPPROTO_UDP;

		iph->check    = 0;

		put_unaligned(np->local_ip.ip, &(iph->saddr));

		put_unaligned(np->remote_ip.ip, &(iph->daddr));

		iph->check    = ip_fast_csum((unsigned char *)iph, iph->ihl);



		eth = skb_push(skb, ETH_HLEN);

		skb_reset_mac_header(skb);

		skb->protocol = eth->h_proto = htons(ETH_P_IP);

	}

	else

		push_ipv4(np, skb, len);



	eth = eth_hdr(skb);

	ether_addr_copy(eth->h_source, np->dev->dev_addr);

	ether_addr_copy(eth->h_dest, np->remote_mac);