1 files changed, 168 insertions, 0 deletions

diff --git a/networking/udhcp/d6_packet.c b/networking/udhcp/d6_packet.c
new file mode 100644
index 000000000..3a1bb3df1
--- /dev/null
+++ b/networking/udhcp/d6_packet.c
@@ -0,0 +1,168 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Copyright (C) 2011 Denys Vlasenko.
+ *
+ * Licensed under GPLv2, see file LICENSE in this source tree.
+ */
+#include "common.h"
+#include "d6_common.h"
+#include "dhcpd.h"
+#include <netinet/in.h>
+#include <netinet/if_ether.h>
+#include <netpacket/packet.h>
+
+#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 2
+void FAST_FUNC d6_dump_packet(struct d6_packet *packet)
+{
+        if (dhcp_verbose < 2)
+                return;
+
+        bb_info_msg(
+                " xid %x"
+                , packet->d6_xid32
+        );
+        //*bin2hex(buf, (void *) packet->chaddr, sizeof(packet->chaddr)) = '\0';
+        //bb_info_msg(" chaddr %s", buf);
+}
+#endif
+
+int FAST_FUNC d6_recv_kernel_packet(struct in6_addr *peer_ipv6
+        UNUSED_PARAM
+        , struct d6_packet *packet, int fd)
+{
+        int bytes;
+
+        memset(packet, 0, sizeof(*packet));
+        bytes = safe_read(fd, packet, sizeof(*packet));
+        if (bytes < 0) {
+                log1("Packet read error, ignoring");
+                return bytes; /* returns -1 */
+        }
+
+        if (bytes < offsetof(struct d6_packet, d6_options)) {
+                bb_info_msg("Packet with bad magic, ignoring");
+                return -2;
+        }
+        log1("Received a packet");
+        d6_dump_packet(packet);
+
+        return bytes;
+}
+
+/* Construct a ipv6+udp header for a packet, send packet */
+int FAST_FUNC d6_send_raw_packet(
+                struct d6_packet *d6_pkt, unsigned d6_pkt_size,
+                struct in6_addr *src_ipv6, int source_port,
+                struct in6_addr *dst_ipv6, int dest_port, const uint8_t *dest_arp,
+                int ifindex)
+{
+        struct sockaddr_ll dest_sll;
+        struct ip6_udp_d6_packet packet;
+        int fd;
+        int result = -1;
+        const char *msg;
+
+        fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IPV6));
+        if (fd < 0) {
+                msg = "socket(%s)";
+                goto ret_msg;
+        }
+
+        memset(&dest_sll, 0, sizeof(dest_sll));
+        memset(&packet, 0, offsetof(struct ip6_udp_d6_packet, data));
+        packet.data = *d6_pkt; /* struct copy */
+
+        dest_sll.sll_family = AF_PACKET;
+        dest_sll.sll_protocol = htons(ETH_P_IPV6);
+        dest_sll.sll_ifindex = ifindex;
+        dest_sll.sll_halen = 6;
+        memcpy(dest_sll.sll_addr, dest_arp, 6);
+
+        if (bind(fd, (struct sockaddr *)&dest_sll, sizeof(dest_sll)) < 0) {
+                msg = "bind(%s)";
+                goto ret_close;
+        }
+
+        packet.ip6.ip6_vfc = (6 << 4); /* 4 bits version, top 4 bits of tclass */
+        if (src_ipv6)
+                packet.ip6.ip6_src = *src_ipv6; /* struct copy */
+        packet.ip6.ip6_dst = *dst_ipv6; /* struct copy */
+        packet.udp.source = htons(source_port);
+        packet.udp.dest = htons(dest_port);
+        /* size, excluding IP header: */
+        packet.udp.len = htons(sizeof(struct udphdr) + d6_pkt_size);
+        packet.ip6.ip6_plen = packet.udp.len;
+        /* UDP checksum skips first four bytes of IP header.
+         * IPv6 'hop limit' field should be 0.
+         * 'next header' field should be summed as if it is in a different
+         * position, therefore we write its value into ip6_hlim:
+         */
+        packet.ip6.ip6_hlim = IPPROTO_UDP;
+        packet.udp.check = inet_cksum((uint16_t *)&packet + 2,
+                                offsetof(struct ip6_udp_d6_packet, data) - 4 + d6_pkt_size);
+        /* fix 'hop limit' and 'next header' after UDP checksumming */
+        packet.ip6.ip6_hlim = 8;
+        packet.ip6.ip6_nxt = IPPROTO_UDP;
+
+        d6_dump_packet(d6_pkt);
+        result = sendto(fd, &packet, offsetof(struct ip6_udp_d6_packet, data) + d6_pkt_size,
+                        /*flags:*/ 0,
+                        (struct sockaddr *) &dest_sll, sizeof(dest_sll)
+        );
+        msg = "sendto";
+ ret_close:
+        close(fd);
+        if (result < 0) {
+ ret_msg:
+                bb_perror_msg(msg, "PACKET");
+        }
+        return result;
+}
+
+/* Let the kernel do all the work for packet generation */
+int FAST_FUNC d6_send_kernel_packet(
+                struct d6_packet *d6_pkt, unsigned d6_pkt_size,
+                struct in6_addr *src_ipv6, int source_port,
+                struct in6_addr *dst_ipv6, int dest_port)
+{
+        struct sockaddr_in6 sa;
+        int fd;
+        int result = -1;
+        const char *msg;
+
+        fd = socket(PF_INET6, SOCK_DGRAM, IPPROTO_UDP);
+        if (fd < 0) {
+                msg = "socket(%s)";
+                goto ret_msg;
+        }
+        setsockopt_reuseaddr(fd);
+
+        memset(&sa, 0, sizeof(sa));
+        sa.sin6_family = AF_INET6;
+        sa.sin6_port = htons(source_port);
+        sa.sin6_addr = *src_ipv6; /* struct copy */
+        if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) == -1) {
+                msg = "bind(%s)";
+                goto ret_close;
+        }
+
+        memset(&sa, 0, sizeof(sa));
+        sa.sin6_family = AF_INET6;
+        sa.sin6_port = htons(dest_port);
+        sa.sin6_addr = *dst_ipv6; /* struct copy */
+        if (connect(fd, (struct sockaddr *)&sa, sizeof(sa)) == -1) {
+                msg = "connect";
+                goto ret_close;
+        }
+
+        d6_dump_packet(d6_pkt);
+        result = safe_write(fd, d6_pkt, d6_pkt_size);
+        msg = "write";
+ ret_close:
+        close(fd);
+        if (result < 0) {
+ ret_msg:
+                bb_perror_msg(msg, "UDP");
+        }
+        return result;
+}