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

+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;

+
+	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;

+
+	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);