Re: [PATCH net-next v3 04/15] quic: provide family ops for address and protocol

[Paolo Abeni <pabeni@redhat.com>]

On 9/19/25 12:34 AM, Xin Long wrote:
> +static int quic_v4_flow_route(struct sock *sk, union quic_addr *da, union quic_addr *sa,
> +			      struct flowi *fl)
> +{
> +	struct flowi4 *fl4;
> +	struct rtable *rt;
> +	struct flowi _fl;
> +
> +	if (__sk_dst_check(sk, 0))
> +		return 1;
> +
> +	fl4 = &_fl.u.ip4;
> +	memset(&_fl, 0x00, sizeof(_fl));
> +	fl4->saddr = sa->v4.sin_addr.s_addr;
> +	fl4->fl4_sport = sa->v4.sin_port;
> +	fl4->daddr = da->v4.sin_addr.s_addr;
> +	fl4->fl4_dport = da->v4.sin_port;
> +	fl4->flowi4_proto = IPPROTO_UDP;
> +	fl4->flowi4_oif = sk->sk_bound_dev_if;

Why you need a local variable? I think you could use the 'fl' argument
directly.

> +
> +	fl4->flowi4_scope = ip_sock_rt_scope(sk);
> +	fl4->flowi4_dscp = inet_sk_dscp(inet_sk(sk));
> +
> +	rt = ip_route_output_key(sock_net(sk), fl4);
> +	if (IS_ERR(rt))
> +		return PTR_ERR(rt);
> +
> +	if (!sa->v4.sin_family) {
> +		sa->v4.sin_family = AF_INET;
> +		sa->v4.sin_addr.s_addr = fl4->saddr;
> +	}
> +	sk_setup_caps(sk, &rt->dst);
> +	memcpy(fl, &_fl, sizeof(_fl));
> +	return 0;
> +}
> +
> +static int quic_v6_flow_route(struct sock *sk, union quic_addr *da, union quic_addr *sa,
> +			      struct flowi *fl)
> +{
> +	struct ipv6_pinfo *np = inet6_sk(sk);
> +	struct ip6_flowlabel *flowlabel;
> +	struct dst_entry *dst;
> +	struct flowi6 *fl6;
> +	struct flowi _fl;
> +
> +	if (__sk_dst_check(sk, np->dst_cookie))
> +		return 1;
> +
> +	fl6 = &_fl.u.ip6;
> +	memset(&_fl, 0x0, sizeof(_fl));
> +	fl6->saddr = sa->v6.sin6_addr;
> +	fl6->fl6_sport = sa->v6.sin6_port;
> +	fl6->daddr = da->v6.sin6_addr;
> +	fl6->fl6_dport = da->v6.sin6_port;
> +	fl6->flowi6_proto = IPPROTO_UDP;
> +	fl6->flowi6_oif = sk->sk_bound_dev_if;

Same here.

> +
> +	if (inet6_test_bit(SNDFLOW, sk)) {
> +		fl6->flowlabel = (da->v6.sin6_flowinfo & IPV6_FLOWINFO_MASK);
> +		if (fl6->flowlabel & IPV6_FLOWLABEL_MASK) {
> +			flowlabel = fl6_sock_lookup(sk, fl6->flowlabel);
> +			if (IS_ERR(flowlabel))
> +				return -EINVAL;
> +			fl6_sock_release(flowlabel);
> +		}
> +	}
> +
> +	dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, NULL);
> +	if (IS_ERR(dst))
> +		return PTR_ERR(dst);
> +
> +	if (!sa->v6.sin6_family) {
> +		sa->v6.sin6_family = AF_INET6;
> +		sa->v6.sin6_addr = fl6->saddr;
> +	}
> +	ip6_dst_store(sk, dst, NULL, NULL);
> +	memcpy(fl, &_fl, sizeof(_fl));
> +	return 0;
> +}
> +
> +static void quic_v4_lower_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl)
> +{
> +	struct quic_skb_cb *cb = QUIC_SKB_CB(skb);
> +	u8 tos = (inet_sk(sk)->tos | cb->ecn), ttl;
> +	struct flowi4 *fl4 = &fl->u.ip4;
> +	struct dst_entry *dst;
> +	__be16 df = 0;
> +
> +	pr_debug("%s: skb: %p, len: %d, num: %llu, %pI4:%d -> %pI4:%d\n", __func__,
> +		 skb, skb->len, cb->number, &fl4->saddr, ntohs(fl4->fl4_sport),
> +		 &fl4->daddr, ntohs(fl4->fl4_dport));
> +
> +	dst = sk_dst_get(sk);
> +	if (!dst) {
> +		kfree_skb(skb);
> +		return;
> +	}
> +	if (ip_dont_fragment(sk, dst) && !skb->ignore_df)
> +		df = htons(IP_DF);
> +
> +	ttl = (u8)ip4_dst_hoplimit(dst);
> +	udp_tunnel_xmit_skb((struct rtable *)dst, sk, skb, fl4->saddr, fl4->daddr,
> +			    tos, ttl, df, fl4->fl4_sport, fl4->fl4_dport, false, false, 0);
> +}
> +
> +static void quic_v6_lower_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl)
> +{
> +	struct quic_skb_cb *cb = QUIC_SKB_CB(skb);
> +	u8 tc = (inet6_sk(sk)->tclass | cb->ecn), ttl;
> +	struct flowi6 *fl6 = &fl->u.ip6;
> +	struct dst_entry *dst;
> +	__be32 label;
> +
> +	pr_debug("%s: skb: %p, len: %d, num: %llu, %pI6c:%d -> %pI6c:%d\n", __func__,
> +		 skb, skb->len, cb->number, &fl6->saddr, ntohs(fl6->fl6_sport),
> +		 &fl6->daddr, ntohs(fl6->fl6_dport));
> +
> +	dst = sk_dst_get(sk);
> +	if (!dst) {
> +		kfree_skb(skb);
> +		return;
> +	}
> +
> +	ttl = (u8)ip6_dst_hoplimit(dst);
> +	label = ip6_make_flowlabel(sock_net(sk), skb, fl6->flowlabel, true, fl6);
> +	udp_tunnel6_xmit_skb(dst, sk, skb, NULL, &fl6->saddr, &fl6->daddr, tc,
> +			     ttl, label, fl6->fl6_sport, fl6->fl6_dport, false, 0);
> +}
> +
> +static void quic_v4_get_msg_addrs(struct sk_buff *skb, union quic_addr *da, union quic_addr *sa)
> +{
> +	struct udphdr *uh = quic_udphdr(skb);
> +
> +	sa->v4.sin_family = AF_INET;
> +	sa->v4.sin_port = uh->source;
> +	sa->v4.sin_addr.s_addr = ip_hdr(skb)->saddr;
> +
> +	da->v4.sin_family = AF_INET;
> +	da->v4.sin_port = uh->dest;
> +	da->v4.sin_addr.s_addr = ip_hdr(skb)->daddr;
> +}
> +
> +static void quic_v6_get_msg_addrs(struct sk_buff *skb, union quic_addr *da, union quic_addr *sa)
> +{
> +	struct udphdr *uh = quic_udphdr(skb);
> +
> +	sa->v6.sin6_family = AF_INET6;
> +	sa->v6.sin6_port = uh->source;
> +	sa->v6.sin6_addr = ipv6_hdr(skb)->saddr;
> +
> +	da->v6.sin6_family = AF_INET6;
> +	da->v6.sin6_port = uh->dest;
> +	da->v6.sin6_addr = ipv6_hdr(skb)->daddr;
> +}
> +
> +static int quic_v4_get_mtu_info(struct sk_buff *skb, u32 *info)
> +{
> +	struct icmphdr *hdr;
> +
> +	hdr = (struct icmphdr *)(skb_network_header(skb) - sizeof(struct icmphdr));
> +	if (hdr->type == ICMP_DEST_UNREACH && hdr->code == ICMP_FRAG_NEEDED) {
> +		*info = ntohs(hdr->un.frag.mtu);
> +		return 0;
> +	}
> +
> +	/* Defer other types' processing to UDP error handler. */
> +	return 1;
> +}
> +
> +static int quic_v6_get_mtu_info(struct sk_buff *skb, u32 *info)
> +{
> +	struct icmp6hdr *hdr;
> +
> +	hdr = (struct icmp6hdr *)(skb_network_header(skb) - sizeof(struct icmp6hdr));
> +	if (hdr->icmp6_type == ICMPV6_PKT_TOOBIG) {
> +		*info = ntohl(hdr->icmp6_mtu);
> +		return 0;
> +	}
> +
> +	/* Defer other types' processing to UDP error handler. */
> +	return 1;
> +}
> +
> +static u8 quic_v4_get_msg_ecn(struct sk_buff *skb)
> +{
> +	return (ip_hdr(skb)->tos & INET_ECN_MASK);
> +}
> +
> +static u8 quic_v6_get_msg_ecn(struct sk_buff *skb)
> +{
> +	return (ipv6_get_dsfield(ipv6_hdr(skb)) & INET_ECN_MASK);
> +}
> +
> +static int quic_v4_get_user_addr(struct sock *sk, union quic_addr *a, struct sockaddr *addr,
> +				 int addr_len)
> +{
> +	u32 len = sizeof(struct sockaddr_in);
> +
> +	if (addr_len < len || addr->sa_family != AF_INET)
> +		return 1;
> +	if (ipv4_is_multicast(quic_addr(addr)->v4.sin_addr.s_addr))
> +		return 1;
> +	memcpy(a, addr, len);
> +	return 0;
> +}
> +
> +static int quic_v6_get_user_addr(struct sock *sk, union quic_addr *a, struct sockaddr *addr,
> +				 int addr_len)
> +{
> +	u32 len = sizeof(struct sockaddr_in);
> +	int type;
> +
> +	if (addr_len < len)
> +		return 1;
> +
> +	if (addr->sa_family != AF_INET6) {
> +		if (ipv6_only_sock(sk))
> +			return 1;
> +		return quic_v4_get_user_addr(sk, a, addr, addr_len);
> +	}
> +
> +	len = sizeof(struct sockaddr_in6);
> +	if (addr_len < len)
> +		return 1;
> +	type = ipv6_addr_type(&quic_addr(addr)->v6.sin6_addr);
> +	if (type != IPV6_ADDR_ANY && !(type & IPV6_ADDR_UNICAST))
> +		return 1;
> +	memcpy(a, addr, len);
> +	return 0;
> +}
> +
> +static void quic_v4_get_pref_addr(struct sock *sk, union quic_addr *addr, u8 **pp, u32 *plen)
> +{
> +	u8 *p = *pp;
> +
> +	memcpy(&addr->v4.sin_addr, p, QUIC_ADDR4_LEN);
> +	p += QUIC_ADDR4_LEN;
> +	memcpy(&addr->v4.sin_port, p, QUIC_PORT_LEN);
> +	p += QUIC_PORT_LEN;
> +	addr->v4.sin_family = AF_INET;
> +	/* Skip over IPv6 address and port, not used for AF_INET sockets. */
> +	p += QUIC_ADDR6_LEN;
> +	p += QUIC_PORT_LEN;
> +
> +	if (!addr->v4.sin_port || quic_v4_is_any_addr(addr) ||
> +	    ipv4_is_multicast(addr->v4.sin_addr.s_addr))
> +		memset(addr, 0, sizeof(*addr));
> +	*plen -= (p - *pp);
> +	*pp = p;
> +}
> +
> +static void quic_v6_get_pref_addr(struct sock *sk, union quic_addr *addr, u8 **pp, u32 *plen)
> +{
> +	u8 *p = *pp;
> +	int type;
> +
> +	/* Skip over IPv4 address and port. */
> +	p += QUIC_ADDR4_LEN;
> +	p += QUIC_PORT_LEN;
> +	/* Try to use IPv6 address and port first. */
> +	memcpy(&addr->v6.sin6_addr, p, QUIC_ADDR6_LEN);
> +	p += QUIC_ADDR6_LEN;
> +	memcpy(&addr->v6.sin6_port, p, QUIC_PORT_LEN);
> +	p += QUIC_PORT_LEN;
> +	addr->v6.sin6_family = AF_INET6;
> +
> +	type = ipv6_addr_type(&addr->v6.sin6_addr);
> +	if (!addr->v6.sin6_port || !(type & IPV6_ADDR_UNICAST)) {
> +		memset(addr, 0, sizeof(*addr));
> +		if (ipv6_only_sock(sk))
> +			goto out;
> +		/* Fallback to IPv4 if IPv6 address is not usable. */
> +		return quic_v4_get_pref_addr(sk, addr, pp, plen);
> +	}
> +out:
> +	*plen -= (p - *pp);
> +	*pp = p;
> +}
> +
> +static void quic_v4_set_pref_addr(struct sock *sk, u8 *p, union quic_addr *addr)
> +{
> +	memcpy(p, &addr->v4.sin_addr, QUIC_ADDR4_LEN);
> +	p += QUIC_ADDR4_LEN;
> +	memcpy(p, &addr->v4.sin_port, QUIC_PORT_LEN);
> +	p += QUIC_PORT_LEN;
> +	memset(p, 0, QUIC_ADDR6_LEN);
> +	p += QUIC_ADDR6_LEN;
> +	memset(p, 0, QUIC_PORT_LEN);
> +}
> +
> +static void quic_v6_set_pref_addr(struct sock *sk, u8 *p, union quic_addr *addr)
> +{
> +	if (addr->sa.sa_family == AF_INET)
> +		return quic_v4_set_pref_addr(sk, p, addr);
> +
> +	memset(p, 0, QUIC_ADDR4_LEN);
> +	p += QUIC_ADDR4_LEN;
> +	memset(p, 0, QUIC_PORT_LEN);
> +	p += QUIC_PORT_LEN;
> +	memcpy(p, &addr->v6.sin6_addr, QUIC_ADDR6_LEN);
> +	p += QUIC_ADDR6_LEN;
> +	memcpy(p, &addr->v6.sin6_port, QUIC_PORT_LEN);
> +}
> +
> +static bool quic_v4_cmp_sk_addr(struct sock *sk, union quic_addr *a, union quic_addr *addr)
> +{
> +	if (a->v4.sin_port != addr->v4.sin_port)
> +		return false;
> +	if (a->v4.sin_family != addr->v4.sin_family)
> +		return false;
> +	if (a->v4.sin_addr.s_addr == htonl(INADDR_ANY) ||
> +	    addr->v4.sin_addr.s_addr == htonl(INADDR_ANY))
> +		return true;
> +	return a->v4.sin_addr.s_addr == addr->v4.sin_addr.s_addr;
> +}
> +
> +static bool quic_v6_cmp_sk_addr(struct sock *sk, union quic_addr *a, union quic_addr *addr)
> +{
> +	if (a->v4.sin_port != addr->v4.sin_port)
> +		return false;
> +
> +	if (a->sa.sa_family == AF_INET && addr->sa.sa_family == AF_INET) {
> +		if (a->v4.sin_addr.s_addr == htonl(INADDR_ANY) ||
> +		    addr->v4.sin_addr.s_addr == htonl(INADDR_ANY))
> +			return true;
> +		return a->v4.sin_addr.s_addr == addr->v4.sin_addr.s_addr;
> +	}
> +
> +	if (a->sa.sa_family != addr->sa.sa_family) {
> +		if (ipv6_only_sock(sk))
> +			return false;
> +		if (a->sa.sa_family == AF_INET6 && ipv6_addr_any(&a->v6.sin6_addr))
> +			return true;
> +		if (a->sa.sa_family == AF_INET && addr->sa.sa_family == AF_INET6 &&
> +		    ipv6_addr_v4mapped(&addr->v6.sin6_addr) &&
> +		    addr->v6.sin6_addr.s6_addr32[3] == a->v4.sin_addr.s_addr)
> +			return true;
> +		if (addr->sa.sa_family == AF_INET && a->sa.sa_family == AF_INET6 &&
> +		    ipv6_addr_v4mapped(&a->v6.sin6_addr) &&
> +		    a->v6.sin6_addr.s6_addr32[3] == addr->v4.sin_addr.s_addr)
> +			return true;
> +		return false;
> +	}
> +
> +	if (ipv6_addr_any(&a->v6.sin6_addr) || ipv6_addr_any(&addr->v6.sin6_addr))
> +		return true;
> +	return ipv6_addr_equal(&a->v6.sin6_addr, &addr->v6.sin6_addr);
> +}
> +
> +static int quic_v4_get_sk_addr(struct socket *sock, struct sockaddr *uaddr, int peer)
> +{
> +	return inet_getname(sock, uaddr, peer);
> +}
> +
> +static int quic_v6_get_sk_addr(struct socket *sock, struct sockaddr *uaddr, int peer)
> +{
> +	union quic_addr *a = quic_addr(uaddr);
> +	int ret;
> +
> +	ret = inet6_getname(sock, uaddr, peer);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (a->sa.sa_family == AF_INET6 && ipv6_addr_v4mapped(&a->v6.sin6_addr)) {
> +		a->v4.sin_family = AF_INET;
> +		a->v4.sin_port = a->v6.sin6_port;
> +		a->v4.sin_addr.s_addr = a->v6.sin6_addr.s6_addr32[3];
> +	}
> +
> +	if (a->sa.sa_family == AF_INET) {
> +		memset(a->v4.sin_zero, 0, sizeof(a->v4.sin_zero));
> +		return sizeof(struct sockaddr_in);
> +	}
> +	return sizeof(struct sockaddr_in6);
> +}
> +
> +static void quic_v4_set_sk_addr(struct sock *sk, union quic_addr *a, bool src)
> +{
> +	if (src) {
> +		inet_sk(sk)->inet_sport = a->v4.sin_port;
> +		inet_sk(sk)->inet_saddr = a->v4.sin_addr.s_addr;
> +	} else {
> +		inet_sk(sk)->inet_dport = a->v4.sin_port;
> +		inet_sk(sk)->inet_daddr = a->v4.sin_addr.s_addr;
> +	}
> +}
> +
> +static void quic_v6_copy_sk_addr(struct in6_addr *skaddr, union quic_addr *a)
> +{
> +	if (a->sa.sa_family == AF_INET) {
> +		skaddr->s6_addr32[0] = 0;
> +		skaddr->s6_addr32[1] = 0;
> +		skaddr->s6_addr32[2] = htonl(0x0000ffff);
> +		skaddr->s6_addr32[3] = a->v4.sin_addr.s_addr;
> +	} else {
> +		*skaddr = a->v6.sin6_addr;
> +	}
> +}
> +
> +static void quic_v6_set_sk_addr(struct sock *sk, union quic_addr *a, bool src)
> +{
> +	if (src) {
> +		inet_sk(sk)->inet_sport = a->v4.sin_port;
> +		quic_v6_copy_sk_addr(&sk->sk_v6_rcv_saddr, a);
> +	} else {
> +		inet_sk(sk)->inet_dport = a->v4.sin_port;
> +		quic_v6_copy_sk_addr(&sk->sk_v6_daddr, a);
> +	}
> +}
> +
> +static void quic_v4_set_sk_ecn(struct sock *sk, u8 ecn)
> +{
> +	inet_sk(sk)->tos = ((inet_sk(sk)->tos & ~INET_ECN_MASK) | ecn);
> +}
> +
> +static void quic_v6_set_sk_ecn(struct sock *sk, u8 ecn)
> +{
> +	quic_v4_set_sk_ecn(sk, ecn);
> +	inet6_sk(sk)->tclass = ((inet6_sk(sk)->tclass & ~INET_ECN_MASK) | ecn);
> +}
> +
> +#define quic_af_ipv4(a)		((a)->sa.sa_family == AF_INET)
> +
> +u32 quic_encap_len(union quic_addr *a)
> +{
> +	return (quic_af_ipv4(a) ? sizeof(struct iphdr) : sizeof(struct ipv6hdr)) +
> +	       sizeof(struct udphdr);
> +}
> +
> +int quic_is_any_addr(union quic_addr *a)
> +{
> +	return quic_af_ipv4(a) ? quic_v4_is_any_addr(a) : quic_v6_is_any_addr(a);
> +}
> +
> +void quic_seq_dump_addr(struct seq_file *seq, union quic_addr *addr)
> +{
> +	quic_af_ipv4(addr) ? quic_v4_seq_dump_addr(seq, addr) : quic_v6_seq_dump_addr(seq, addr);
> +}
> +
> +void quic_udp_conf_init(struct sock *sk, struct udp_port_cfg *conf, union quic_addr *a)
> +{
> +	quic_af_ipv4(a) ? quic_v4_udp_conf_init(sk, conf, a) : quic_v6_udp_conf_init(sk, conf, a);
> +}
> +
> +int quic_flow_route(struct sock *sk, union quic_addr *da, union quic_addr *sa, struct flowi *fl)
> +{
> +	return quic_af_ipv4(da) ? quic_v4_flow_route(sk, da, sa, fl)
> +				: quic_v6_flow_route(sk, da, sa, fl);
> +}
> +
> +void quic_lower_xmit(struct sock *sk, struct sk_buff *skb, union quic_addr *da, struct flowi *fl)
> +{
> +	quic_af_ipv4(da) ? quic_v4_lower_xmit(sk, skb, fl) : quic_v6_lower_xmit(sk, skb, fl);
> +}
> +
> +#define quic_skb_ipv4(skb)	(ip_hdr(skb)->version == 4)
> +
> +void quic_get_msg_addrs(struct sk_buff *skb, union quic_addr *da, union quic_addr *sa)
> +{
> +	memset(sa, 0, sizeof(*sa));
> +	memset(da, 0, sizeof(*da));
> +	quic_skb_ipv4(skb) ? quic_v4_get_msg_addrs(skb, da, sa)
> +			   : quic_v6_get_msg_addrs(skb, da, sa);
> +}
> +
> +int quic_get_mtu_info(struct sk_buff *skb, u32 *info)
> +{
> +	return quic_skb_ipv4(skb) ? quic_v4_get_mtu_info(skb, info)
> +				  : quic_v6_get_mtu_info(skb, info);
> +}
> +
> +u8 quic_get_msg_ecn(struct sk_buff *skb)
> +{
> +	return quic_skb_ipv4(skb) ? quic_v4_get_msg_ecn(skb) : quic_v6_get_msg_ecn(skb);
> +}
> +
> +#define quic_pf_ipv4(sk)	((sk)->sk_family == PF_INET)
> +
> +int quic_get_user_addr(struct sock *sk, union quic_addr *a, struct sockaddr *addr, int addr_len)
> +{
> +	memset(a, 0, sizeof(*a));
> +	return quic_pf_ipv4(sk) ? quic_v4_get_user_addr(sk, a, addr, addr_len)
> +				: quic_v6_get_user_addr(sk, a, addr, addr_len);

Minor nit: I think the most idiomatic way to express the abvoe is:

return quic_pf_ipv4(sk) ? quic_v4_get_user_addr(sk, a, addr, addr_len) :
			  quic_v6_get_user_addr(sk, a, addr, addr_len);

(other cases below)

/P