Re: [PATCH net-next v4 04/15] quic: provide family ops for address and protocol

[Paolo Abeni <pabeni@redhat.com>]

On 10/29/25 3:35 PM, 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;
> +
> +	if (__sk_dst_check(sk, 0))
> +		return 1;
> +
> +	memset(fl, 0x00, sizeof(*fl));
> +	fl4 = &fl->u.ip4;
> +	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;
> +
> +	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) {

The above check is strange. Any special reason to not use
quic_v4_is_any_addr()?

> +		sa->v4.sin_family = AF_INET;
> +		sa->v4.sin_addr.s_addr = fl4->saddr;
> +	}
> +	sk_setup_caps(sk, &rt->dst);
> +	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;
> +
> +	if (__sk_dst_check(sk, np->dst_cookie))
> +		return 1;
> +
> +	memset(fl, 0x00, sizeof(*fl));
> +	fl6 = &fl->u.ip6;
> +	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;
> +
> +	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) {

(similar question here)

[...]
> +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));

Noting the above relies on headers being already pulled in the linear
part. Later patch will do skb_linarize(), but that looks overkill and
should hit performance badly. Instead you should use pskb_may_pull() &&
friends.

> +	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;
> +}

It looks like the above function is not used in this series?!? (well
it's called by quic_get_user_addr() which in turn is unsed.

Perhaps drop from here and add later as needed?

Also the name sounds possibly misleading, I read it as it should copy
data to user-space and return value could possibly be an errnum.

> +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;
> +}

Similarly unused?

> +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 &&

Below this code assumes that sa_family is either AF_INET or AF_INET6. If
such assumtion hold, you should use here, too. and drop the
'addr->sa.sa_family == AF_INET6' condition.

> +		    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;

Nothing this branch does not handle the 'ipv6_addr_any(&addr->v6.sin6_addr)'

/P