auto import from //depot/cupcake/@135843

1 files changed, 239 insertions, 0 deletions

diff --git a/libnetutils/packet.c b/libnetutils/packet.c
new file mode 100644
index 0000000..9388345
--- /dev/null
+++ b/libnetutils/packet.c
@@ -0,0 +1,239 @@
+/*
+ * Copyright 2008, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); 
+ * you may not use this file except in compliance with the License. 
+ * You may obtain a copy of the License at 
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0 
+ *
+ * Unless required by applicable law or agreed to in writing, software 
+ * distributed under the License is distributed on an "AS IS" BASIS, 
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
+ * See the License for the specific language governing permissions and 
+ * limitations under the License.
+ */
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/uio.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netinet/ip.h>
+#include <netinet/udp.h>
+#include <linux/if_packet.h>
+#include <linux/if_ether.h>
+#include <errno.h>
+
+#ifdef ANDROID
+#define LOG_TAG "DHCP"
+#include <cutils/log.h>
+#else
+#include <stdio.h>
+#include <string.h>
+#define LOGD printf
+#define LOGW printf
+#endif
+
+#include "dhcpmsg.h"
+
+int fatal();
+
+int open_raw_socket(const char *ifname, uint8_t *hwaddr, int if_index)
+{
+    int s, flag;
+    struct sockaddr_ll bindaddr;
+
+    if((s = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP))) < 0) {
+        return fatal("socket(PF_PACKET)");
+    }
+
+    memset(&bindaddr, 0, sizeof(bindaddr));
+    bindaddr.sll_family = AF_PACKET;
+    bindaddr.sll_protocol = htons(ETH_P_IP);
+    bindaddr.sll_halen = ETH_ALEN;
+    memcpy(bindaddr.sll_addr, hwaddr, ETH_ALEN);
+    bindaddr.sll_ifindex = if_index;
+
+    if (bind(s, (struct sockaddr *)&bindaddr, sizeof(bindaddr)) < 0) {
+        return fatal("Cannot bind raw socket to interface");
+    }
+
+    return s;
+}
+
+static uint32_t checksum(void *buffer, unsigned int count, uint32_t startsum)
+{
+    uint16_t *up = (uint16_t *)buffer;
+    uint32_t sum = startsum;
+    uint32_t upper16;
+
+    while (count > 1) {
+        sum += *up++;
+        count -= 2;
+    }
+    if (count > 0) {
+        sum += (uint16_t) *(uint8_t *)up;
+    }
+    while ((upper16 = (sum >> 16)) != 0) {
+        sum = (sum & 0xffff) + upper16;
+    }
+    return sum;
+}
+
+static uint32_t finish_sum(uint32_t sum)
+{
+    return ~sum & 0xffff;
+}
+
+int send_packet(int s, int if_index, struct dhcp_msg *msg, int size,
+                uint32_t saddr, uint32_t daddr, uint32_t sport, uint32_t dport)
+{
+    struct iphdr ip;
+    struct udphdr udp;
+    struct iovec iov[3];
+    uint32_t udpsum;
+    uint16_t temp;
+    struct msghdr msghdr;
+    struct sockaddr_ll destaddr;
+
+    ip.version = IPVERSION;
+    ip.ihl = sizeof(ip) >> 2;
+    ip.tos = 0;
+    ip.tot_len = htons(sizeof(ip) + sizeof(udp) + size);
+    ip.id = 0;
+    ip.frag_off = 0;
+    ip.ttl = IPDEFTTL;
+    ip.protocol = IPPROTO_UDP;
+    ip.check = 0;
+    ip.saddr = saddr;
+    ip.daddr = daddr;
+    ip.check = finish_sum(checksum(&ip, sizeof(ip), 0));
+
+    udp.source = htons(sport);
+    udp.dest = htons(dport);
+    udp.len = htons(sizeof(udp) + size);
+    udp.check = 0;
+
+    /* Calculate checksum for pseudo header */
+    udpsum = checksum(&ip.saddr, sizeof(ip.saddr), 0);
+    udpsum = checksum(&ip.daddr, sizeof(ip.daddr), udpsum);
+    temp = htons(IPPROTO_UDP);
+    udpsum = checksum(&temp, sizeof(temp), udpsum);
+    temp = udp.len;
+    udpsum = checksum(&temp, sizeof(temp), udpsum);
+
+    /* Add in the checksum for the udp header */
+    udpsum = checksum(&udp, sizeof(udp), udpsum);
+
+    /* Add in the checksum for the data */
+    udpsum = checksum(msg, size, udpsum);
+    udp.check = finish_sum(udpsum);
+
+    iov[0].iov_base = (char *)&ip;
+    iov[0].iov_len = sizeof(ip);
+    iov[1].iov_base = (char *)&udp;
+    iov[1].iov_len = sizeof(udp);
+    iov[2].iov_base = (char *)msg;
+    iov[2].iov_len = size;
+    memset(&destaddr, 0, sizeof(destaddr));
+    destaddr.sll_family = AF_PACKET;
+    destaddr.sll_protocol = htons(ETH_P_IP);
+    destaddr.sll_ifindex = if_index;
+    destaddr.sll_halen = ETH_ALEN;
+    memcpy(destaddr.sll_addr, "\xff\xff\xff\xff\xff\xff", ETH_ALEN);
+
+    msghdr.msg_name = &destaddr;
+    msghdr.msg_namelen = sizeof(destaddr);
+    msghdr.msg_iov = iov;
+    msghdr.msg_iovlen = sizeof(iov) / sizeof(struct iovec);
+    msghdr.msg_flags = 0;
+    msghdr.msg_control = 0;
+    msghdr.msg_controllen = 0;
+    return sendmsg(s, &msghdr, 0);
+}
+
+int receive_packet(int s, struct dhcp_msg *msg)
+{
+    int nread;
+    int is_valid;
+    struct dhcp_packet {
+        struct iphdr ip;
+        struct udphdr udp;
+        struct dhcp_msg dhcp;
+    } packet;
+    int dhcp_size;
+    uint32_t sum;
+    uint16_t temp;
+    uint32_t saddr, daddr;
+
+    nread = read(s, &packet, sizeof(packet));
+    if (nread < 0) {
+        return -1;
+    }
+    /*
+     * The raw packet interface gives us all packets received by the
+     * network interface. We need to filter out all packets that are
+     * not meant for us.
+     */
+    is_valid = 0;
+    if (nread < (int)(sizeof(struct iphdr) + sizeof(struct udphdr))) {
+#if VERBOSE
+        LOGD("Packet is too small (%d) to be a UDP datagram", nread);
+#endif
+    } else if (packet.ip.version != IPVERSION || packet.ip.ihl != (sizeof(packet.ip) >> 2)) {
+#if VERBOSE
+        LOGD("Not a valid IP packet");
+#endif
+    } else if (nread < ntohs(packet.ip.tot_len)) {
+#if VERBOSE
+        LOGD("Packet was truncated (read %d, needed %d)", nread, ntohs(packet.ip.tot_len));
+#endif
+    } else if (packet.ip.protocol != IPPROTO_UDP) {
+#if VERBOSE
+        LOGD("IP protocol (%d) is not UDP", packet.ip.protocol);
+#endif
+    } else if (packet.udp.dest != htons(PORT_BOOTP_CLIENT)) {
+#if VERBOSE
+        LOGD("UDP dest port (%d) is not DHCP client", ntohs(packet.udp.dest));
+#endif
+    } else {
+        is_valid = 1;
+    }
+
+    if (!is_valid) {
+        return -1;
+    }
+
+    /* Seems like it's probably a valid DHCP packet */
+    /* validate IP header checksum */
+    sum = finish_sum(checksum(&packet.ip, sizeof(packet.ip), 0));
+    if (sum != 0) {
+        LOGW("IP header checksum failure (0x%x)", packet.ip.check);
+        return -1;
+    }
+    /*
+     * Validate the UDP checksum.
+     * Since we don't need the IP header anymore, we "borrow" it
+     * to construct the pseudo header used in the checksum calculation.
+     */
+    dhcp_size = ntohs(packet.udp.len) - sizeof(packet.udp);
+    saddr = packet.ip.saddr;
+    daddr = packet.ip.daddr;
+    nread = ntohs(packet.ip.tot_len);
+    memset(&packet.ip, 0, sizeof(packet.ip));
+    packet.ip.saddr = saddr;
+    packet.ip.daddr = daddr;
+    packet.ip.protocol = IPPROTO_UDP;
+    packet.ip.tot_len = packet.udp.len;
+    temp = packet.udp.check;
+    packet.udp.check = 0;
+    sum = finish_sum(checksum(&packet, nread, 0));
+    packet.udp.check = temp;
+    if (temp != sum) {
+        LOGW("UDP header checksum failure (0x%x should be 0x%x)", sum, temp);
+        return -1;
+    }
+    memcpy(msg, &packet.dhcp, dhcp_size);
+    return dhcp_size;
+}