Add a "fork" of musl as //fusl.

fusl/src/network/getifaddrs.c

Index: fusl/src/network/getifaddrs.c
diff --git a/fusl/src/network/getifaddrs.c b/fusl/src/network/getifaddrs.c
new file mode 100644
index 0000000000000000000000000000000000000000..fed75bd8d9293aa51c9e85461ca533dcf1d1ddae
--- /dev/null
+++ b/fusl/src/network/getifaddrs.c
@@ -0,0 +1,216 @@
+#define _GNU_SOURCE
+#include <errno.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <ifaddrs.h>
+#include <syscall.h>
+#include <net/if.h>
+#include <netinet/in.h>
+#include "netlink.h"
+
+#define IFADDRS_HASH_SIZE 64
+
+/* getifaddrs() reports hardware addresses with PF_PACKET that implies
+ * struct sockaddr_ll.  But e.g. Infiniband socket address length is
+ * longer than sockaddr_ll.ssl_addr[8] can hold. Use this hack struct
+ * to extend ssl_addr - callers should be able to still use it. */
+struct sockaddr_ll_hack {
+	unsigned short sll_family, sll_protocol;
+	int sll_ifindex;
+	unsigned short sll_hatype;
+	unsigned char sll_pkttype, sll_halen;
+	unsigned char sll_addr[24];
+};
+
+union sockany {
+	struct sockaddr sa;
+	struct sockaddr_ll_hack ll;
+	struct sockaddr_in v4;
+	struct sockaddr_in6 v6;
+};
+
+struct ifaddrs_storage {
+	struct ifaddrs ifa;
+	struct ifaddrs_storage *hash_next;
+	union sockany addr, netmask, ifu;
+	unsigned int index;
+	char name[IFNAMSIZ+1];
+};
+
+struct ifaddrs_ctx {
+	struct ifaddrs_storage *first;
+	struct ifaddrs_storage *last;
+	struct ifaddrs_storage *hash[IFADDRS_HASH_SIZE];
+};
+
+void freeifaddrs(struct ifaddrs *ifp)
+{
+	struct ifaddrs *n;
+	while (ifp) {
+		n = ifp->ifa_next;
+		free(ifp);
+		ifp = n;
+	}
+}
+
+static void copy_addr(struct sockaddr **r, int af, union sockany *sa, void *addr, size_t addrlen, int ifindex)
+{
+	uint8_t *dst;
+	int len;
+
+	switch (af) {
+	case AF_INET:
+		dst = (uint8_t*) &sa->v4.sin_addr;
+		len = 4;
+		break;
+	case AF_INET6:
+		dst = (uint8_t*) &sa->v6.sin6_addr;
+		len = 16;
+		if (IN6_IS_ADDR_LINKLOCAL(addr) || IN6_IS_ADDR_MC_LINKLOCAL(addr))
+			sa->v6.sin6_scope_id = ifindex;
+		break;
+	default:
+		return;
+	}
+	if (addrlen < len) return;
+	sa->sa.sa_family = af;
+	memcpy(dst, addr, len);
+	*r = &sa->sa;
+}
+
+static void gen_netmask(struct sockaddr **r, int af, union sockany *sa, int prefixlen)
+{
+	uint8_t addr[16] = {0};
+	int i;
+
+	if (prefixlen > 8*sizeof(addr)) prefixlen = 8*sizeof(addr);
+	i = prefixlen / 8;
+	memset(addr, 0xff, i);
+	if (i < sizeof(addr)) addr[i++] = 0xff << (8 - (prefixlen % 8));
+	copy_addr(r, af, sa, addr, sizeof(addr), 0);
+}
+
+static void copy_lladdr(struct sockaddr **r, union sockany *sa, void *addr, size_t addrlen, int ifindex, unsigned short hatype)
+{
+	if (addrlen > sizeof(sa->ll.sll_addr)) return;
+	sa->ll.sll_family = AF_PACKET;
+	sa->ll.sll_ifindex = ifindex;
+	sa->ll.sll_hatype = hatype;
+	sa->ll.sll_halen = addrlen;
+	memcpy(sa->ll.sll_addr, addr, addrlen);
+	*r = &sa->sa;
+}
+
+static int netlink_msg_to_ifaddr(void *pctx, struct nlmsghdr *h)
+{
+	struct ifaddrs_ctx *ctx = pctx;
+	struct ifaddrs_storage *ifs, *ifs0;
+	struct ifinfomsg *ifi = NLMSG_DATA(h);
+	struct ifaddrmsg *ifa = NLMSG_DATA(h);
+	struct rtattr *rta;
+	int stats_len = 0;
+
+	if (h->nlmsg_type == RTM_NEWLINK) {
+		for (rta = NLMSG_RTA(h, sizeof(*ifi)); NLMSG_RTAOK(rta, h); rta = RTA_NEXT(rta)) {
+			if (rta->rta_type != IFLA_STATS) continue;
+			stats_len = RTA_DATALEN(rta);
+			break;
+		}
+	} else {
+		for (ifs0 = ctx->hash[ifa->ifa_index % IFADDRS_HASH_SIZE]; ifs0; ifs0 = ifs0->hash_next)
+			if (ifs0->index == ifa->ifa_index)
+				break;
+		if (!ifs0) return 0;
+	}
+
+	ifs = calloc(1, sizeof(struct ifaddrs_storage) + stats_len);
+	if (ifs == 0) return -1;
+
+	if (h->nlmsg_type == RTM_NEWLINK) {
+		ifs->index = ifi->ifi_index;
+		ifs->ifa.ifa_flags = ifi->ifi_flags;
+
+		for (rta = NLMSG_RTA(h, sizeof(*ifi)); NLMSG_RTAOK(rta, h); rta = RTA_NEXT(rta)) {
+			switch (rta->rta_type) {
+			case IFLA_IFNAME:
+				if (RTA_DATALEN(rta) < sizeof(ifs->name)) {
+					memcpy(ifs->name, RTA_DATA(rta), RTA_DATALEN(rta));
+					ifs->ifa.ifa_name = ifs->name;
+				}
+				break;
+			case IFLA_ADDRESS:
+				copy_lladdr(&ifs->ifa.ifa_addr, &ifs->addr, RTA_DATA(rta), RTA_DATALEN(rta), ifi->ifi_index, ifi->ifi_type);
+				break;
+			case IFLA_BROADCAST:
+				copy_lladdr(&ifs->ifa.ifa_broadaddr, &ifs->ifu, RTA_DATA(rta), RTA_DATALEN(rta), ifi->ifi_index, ifi->ifi_type);
+				break;
+			case IFLA_STATS:
+				ifs->ifa.ifa_data = (void*)(ifs+1);
+				memcpy(ifs->ifa.ifa_data, RTA_DATA(rta), RTA_DATALEN(rta));
+				break;
+			}
+		}
+		if (ifs->ifa.ifa_name) {
+			unsigned int bucket = ifs->index % IFADDRS_HASH_SIZE;
+			ifs->hash_next = ctx->hash[bucket];
+			ctx->hash[bucket] = ifs;
+		}
+	} else {
+		ifs->ifa.ifa_name = ifs0->ifa.ifa_name;
+		ifs->ifa.ifa_flags = ifs0->ifa.ifa_flags;
+		for (rta = NLMSG_RTA(h, sizeof(*ifa)); NLMSG_RTAOK(rta, h); rta = RTA_NEXT(rta)) {
+			switch (rta->rta_type) {
+			case IFA_ADDRESS:
+				/* If ifa_addr is already set we, received an IFA_LOCAL before
+				 * so treat this as destination address */
+				if (ifs->ifa.ifa_addr)
+					copy_addr(&ifs->ifa.ifa_dstaddr, ifa->ifa_family, &ifs->ifu, RTA_DATA(rta), RTA_DATALEN(rta), ifa->ifa_index);
+				else
+					copy_addr(&ifs->ifa.ifa_addr, ifa->ifa_family, &ifs->addr, RTA_DATA(rta), RTA_DATALEN(rta), ifa->ifa_index);
+				break;
+			case IFA_BROADCAST:
+				copy_addr(&ifs->ifa.ifa_broadaddr, ifa->ifa_family, &ifs->ifu, RTA_DATA(rta), RTA_DATALEN(rta), ifa->ifa_index);
+				break;
+			case IFA_LOCAL:
+				/* If ifa_addr is set and we get IFA_LOCAL, assume we have
+				 * a point-to-point network. Move address to correct field. */
+				if (ifs->ifa.ifa_addr) {
+					ifs->ifu = ifs->addr;
+					ifs->ifa.ifa_dstaddr = &ifs->ifu.sa;
+					memset(&ifs->addr, 0, sizeof(ifs->addr));
+				}
+				copy_addr(&ifs->ifa.ifa_addr, ifa->ifa_family, &ifs->addr, RTA_DATA(rta), RTA_DATALEN(rta), ifa->ifa_index);
+				break;
+			case IFA_LABEL:
+				if (RTA_DATALEN(rta) < sizeof(ifs->name)) {
+					memcpy(ifs->name, RTA_DATA(rta), RTA_DATALEN(rta));
+					ifs->ifa.ifa_name = ifs->name;
+				}
+				break;
+			}
+		}
+		if (ifs->ifa.ifa_addr)
+			gen_netmask(&ifs->ifa.ifa_netmask, ifa->ifa_family, &ifs->netmask, ifa->ifa_prefixlen);
+	}
+
+	if (ifs->ifa.ifa_name) {
+		if (!ctx->first) ctx->first = ifs;
+		if (ctx->last) ctx->last->ifa.ifa_next = &ifs->ifa;
+		ctx->last = ifs;
+	} else {
+		free(ifs);
+	}
+	return 0;
+}
+
+int getifaddrs(struct ifaddrs **ifap)
+{
+	struct ifaddrs_ctx _ctx, *ctx = &_ctx;
+	int r;
+	memset(ctx, 0, sizeof *ctx);
+	r = __rtnetlink_enumerate(AF_UNSPEC, AF_UNSPEC, netlink_msg_to_ifaddr, ctx);
+	if (r == 0) *ifap = &ctx->first->ifa;
+	else freeifaddrs(&ctx->first->ifa);
+	return r;
+}