diff options
Diffstat (limited to 'src/customdhcpcd/socket.c')
| -rw-r--r-- | src/customdhcpcd/socket.c | 1064 |
1 files changed, 555 insertions, 509 deletions
diff --git a/src/customdhcpcd/socket.c b/src/customdhcpcd/socket.c index 58ad6c5..9cb1227 100644 --- a/src/customdhcpcd/socket.c +++ b/src/customdhcpcd/socket.c @@ -65,583 +65,629 @@ #endif /* Broadcast address for IPoIB */ -static const uint8_t ipv4_bcast_addr[] = { - 0x00, 0xff, 0xff, 0xff, - 0xff, 0x12, 0x40, 0x1b, 0x00, 0x00, 0x00, 0x00, - 0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff +static const uint8_t ipv4_bcast_addr[] = +{ + 0x00, 0xff, 0xff, 0xff, + 0xff, 0x12, 0x40, 0x1b, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff }; /* Credit where credit is due :) * The below BPF filter is taken from ISC DHCP */ -static struct bpf_insn dhcp_bpf_filter [] = { - /* Make sure this is an IP packet... */ - BPF_STMT (BPF_LD + BPF_H + BPF_ABS, 12), - BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_IP, 0, 8), +static struct bpf_insn dhcp_bpf_filter [] = +{ + /* Make sure this is an IP packet... */ + BPF_STMT (BPF_LD + BPF_H + BPF_ABS, 12), + BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_IP, 0, 8), - /* Make sure it's a UDP packet... */ - BPF_STMT (BPF_LD + BPF_B + BPF_ABS, 23), - BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 0, 6), + /* Make sure it's a UDP packet... */ + BPF_STMT (BPF_LD + BPF_B + BPF_ABS, 23), + BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 0, 6), - /* Make sure this isn't a fragment... */ - BPF_STMT (BPF_LD + BPF_H + BPF_ABS, 20), - BPF_JUMP (BPF_JMP + BPF_JSET + BPF_K, 0x1fff, 4, 0), + /* Make sure this isn't a fragment... */ + BPF_STMT (BPF_LD + BPF_H + BPF_ABS, 20), + BPF_JUMP (BPF_JMP + BPF_JSET + BPF_K, 0x1fff, 4, 0), - /* Get the IP header length... */ - BPF_STMT (BPF_LDX + BPF_B + BPF_MSH, 14), + /* Get the IP header length... */ + BPF_STMT (BPF_LDX + BPF_B + BPF_MSH, 14), - /* Make sure it's to the right port... */ - BPF_STMT (BPF_LD + BPF_H + BPF_IND, 16), - BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, DHCP_CLIENT_PORT, 0, 1), + /* Make sure it's to the right port... */ + BPF_STMT (BPF_LD + BPF_H + BPF_IND, 16), + BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, DHCP_CLIENT_PORT, 0, 1), - /* If we passed all the tests, ask for the whole packet. */ - BPF_STMT (BPF_RET + BPF_K, ~0U), + /* If we passed all the tests, ask for the whole packet. */ + BPF_STMT (BPF_RET + BPF_K, ~0U), - /* Otherwise, drop it. */ - BPF_STMT (BPF_RET + BPF_K, 0), + /* Otherwise, drop it. */ + BPF_STMT (BPF_RET + BPF_K, 0), }; -static struct bpf_insn arp_bpf_filter [] = { - /* Make sure this is an ARP packet... */ - BPF_STMT (BPF_LD + BPF_H + BPF_ABS, 12), - BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_ARP, 0, 3), +static struct bpf_insn arp_bpf_filter [] = +{ + /* Make sure this is an ARP packet... */ + BPF_STMT (BPF_LD + BPF_H + BPF_ABS, 12), + BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_ARP, 0, 3), - /* Make sure this is an ARP REPLY... */ - BPF_STMT (BPF_LD + BPF_H + BPF_ABS, 20), - BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REPLY, 0, 1), + /* Make sure this is an ARP REPLY... */ + BPF_STMT (BPF_LD + BPF_H + BPF_ABS, 20), + BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REPLY, 0, 1), - /* If we passed all the tests, ask for the whole packet. */ - BPF_STMT (BPF_RET + BPF_K, ~0U), + /* If we passed all the tests, ask for the whole packet. */ + BPF_STMT (BPF_RET + BPF_K, ~0U), - /* Otherwise, drop it. */ - BPF_STMT (BPF_RET + BPF_K, 0), + /* Otherwise, drop it. */ + BPF_STMT (BPF_RET + BPF_K, 0), }; void setup_packet_filters (void) { #ifdef __linux__ - /* We need to massage the filters for Linux cooked packets */ - dhcp_bpf_filter[1].jf = 0; /* skip the IP packet type check */ - dhcp_bpf_filter[2].k -= ETH_HLEN; - dhcp_bpf_filter[4].k -= ETH_HLEN; - dhcp_bpf_filter[6].k -= ETH_HLEN; - dhcp_bpf_filter[7].k -= ETH_HLEN; - - arp_bpf_filter[1].jf = 0; /* skip the IP packet type check */ - arp_bpf_filter[2].k -= ETH_HLEN; + /* We need to massage the filters for Linux cooked packets */ + dhcp_bpf_filter[1].jf = 0; /* skip the IP packet type check */ + dhcp_bpf_filter[2].k -= ETH_HLEN; + dhcp_bpf_filter[4].k -= ETH_HLEN; + dhcp_bpf_filter[6].k -= ETH_HLEN; + dhcp_bpf_filter[7].k -= ETH_HLEN; + + arp_bpf_filter[1].jf = 0; /* skip the IP packet type check */ + arp_bpf_filter[2].k -= ETH_HLEN; #endif } static uint16_t checksum (unsigned char *addr, uint16_t len) { - uint32_t sum = 0; - union - { - unsigned char *addr; - uint16_t *i; - } p; - uint16_t nleft = len; - - p.addr = addr; - while (nleft > 1) { - sum += *p.i++; - nleft -= 2; - } - - if (nleft == 1) { - uint8_t a = 0; - memcpy (&a, p.i, 1); - sum += ntohs (a) << 8; - } - - sum = (sum >> 16) + (sum & 0xffff); - sum += (sum >> 16); - - return ~sum; + uint32_t sum = 0; + union + { + unsigned char *addr; + uint16_t *i; + } p; + uint16_t nleft = len; + + p.addr = addr; + while (nleft > 1) + { + sum += *p.i++; + nleft -= 2; + } + + if (nleft == 1) + { + uint8_t a = 0; + memcpy (&a, p.i, 1); + sum += ntohs (a) << 8; + } + + sum = (sum >> 16) + (sum & 0xffff); + sum += (sum >> 16); + + return ~sum; } void make_dhcp_packet(struct udp_dhcp_packet *packet, - const unsigned char *data, size_t length, - struct in_addr source, struct in_addr dest) + const unsigned char *data, size_t length, + struct in_addr source, struct in_addr dest) { - struct ip *ip = &packet->ip; - struct udphdr *udp = &packet->udp; - - /* OK, this is important :) - * We copy the data to our packet and then create a small part of the - * ip structure and an invalid ip_len (basically udp length). - * We then fill the udp structure and put the checksum - * of the whole packet into the udp checksum. - * Finally we complete the ip structure and ip checksum. - * If we don't do the ordering like so then the udp checksum will be - * broken, so find another way of doing it! */ - - memcpy (&packet->dhcp, data, length); - - ip->ip_p = IPPROTO_UDP; - ip->ip_src.s_addr = source.s_addr; - if (dest.s_addr == 0) - ip->ip_dst.s_addr = INADDR_BROADCAST; - else - ip->ip_dst.s_addr = dest.s_addr; - - udp->uh_sport = htons (DHCP_CLIENT_PORT); - udp->uh_dport = htons (DHCP_SERVER_PORT); - udp->uh_ulen = htons (sizeof (*udp) + length); - ip->ip_len = udp->uh_ulen; - udp->uh_sum = checksum ((unsigned char *) packet, sizeof (*packet)); - - ip->ip_v = IPVERSION; - ip->ip_hl = 5; - ip->ip_id = 0; - ip->ip_tos = IPTOS_LOWDELAY; - ip->ip_len = htons (sizeof (*ip) + sizeof (*udp) + length); - ip->ip_id = 0; - ip->ip_off = htons (IP_DF); /* Don't fragment */ - ip->ip_ttl = IPDEFTTL; - - ip->ip_sum = checksum ((unsigned char *) ip, sizeof (*ip)); + struct ip *ip = &packet->ip; + struct udphdr *udp = &packet->udp; + + /* OK, this is important :) + * We copy the data to our packet and then create a small part of the + * ip structure and an invalid ip_len (basically udp length). + * We then fill the udp structure and put the checksum + * of the whole packet into the udp checksum. + * Finally we complete the ip structure and ip checksum. + * If we don't do the ordering like so then the udp checksum will be + * broken, so find another way of doing it! */ + + memcpy (&packet->dhcp, data, length); + + ip->ip_p = IPPROTO_UDP; + ip->ip_src.s_addr = source.s_addr; + if (dest.s_addr == 0) + ip->ip_dst.s_addr = INADDR_BROADCAST; + else + ip->ip_dst.s_addr = dest.s_addr; + + udp->uh_sport = htons (DHCP_CLIENT_PORT); + udp->uh_dport = htons (DHCP_SERVER_PORT); + udp->uh_ulen = htons (sizeof (*udp) + length); + ip->ip_len = udp->uh_ulen; + udp->uh_sum = checksum ((unsigned char *) packet, sizeof (*packet)); + + ip->ip_v = IPVERSION; + ip->ip_hl = 5; + ip->ip_id = 0; + ip->ip_tos = IPTOS_LOWDELAY; + ip->ip_len = htons (sizeof (*ip) + sizeof (*udp) + length); + ip->ip_id = 0; + ip->ip_off = htons (IP_DF); /* Don't fragment */ + ip->ip_ttl = IPDEFTTL; + + ip->ip_sum = checksum ((unsigned char *) ip, sizeof (*ip)); } static int valid_dhcp_packet (unsigned char *data) { - union - { - unsigned char *data; - struct udp_dhcp_packet *packet; - } d; - uint16_t bytes; - uint16_t ipsum; - uint16_t iplen; - uint16_t udpsum; - struct in_addr source; - struct in_addr dest; - int retval = 0; - - d.data = data; - bytes = ntohs (d.packet->ip.ip_len); - ipsum = d.packet->ip.ip_sum; - iplen = d.packet->ip.ip_len; - udpsum = d.packet->udp.uh_sum; - - d.data = data; - d.packet->ip.ip_sum = 0; - if (ipsum != checksum ((unsigned char *) &d.packet->ip, - sizeof (d.packet->ip))) - { - logger (LOG_DEBUG, "bad IP header checksum, ignoring"); - retval = -1; - goto eexit; - } - - memcpy (&source, &d.packet->ip.ip_src, sizeof (d.packet->ip.ip_src)); - memcpy (&dest, &d.packet->ip.ip_dst, sizeof (d.packet->ip.ip_dst)); - memset (&d.packet->ip, 0, sizeof (d.packet->ip)); - d.packet->udp.uh_sum = 0; - - d.packet->ip.ip_p = IPPROTO_UDP; - memcpy (&d.packet->ip.ip_src, &source, sizeof (d.packet->ip.ip_src)); - memcpy (&d.packet->ip.ip_dst, &dest, sizeof (d.packet->ip.ip_dst)); - d.packet->ip.ip_len = d.packet->udp.uh_ulen; - if (udpsum && udpsum != checksum (d.data, bytes)) { - logger (LOG_ERR, "bad UDP checksum, ignoring"); - retval = -1; - } + union + { + unsigned char *data; + struct udp_dhcp_packet *packet; + } d; + uint16_t bytes; + uint16_t ipsum; + uint16_t iplen; + uint16_t udpsum; + struct in_addr source; + struct in_addr dest; + int retval = 0; + + d.data = data; + bytes = ntohs (d.packet->ip.ip_len); + ipsum = d.packet->ip.ip_sum; + iplen = d.packet->ip.ip_len; + udpsum = d.packet->udp.uh_sum; + + d.data = data; + d.packet->ip.ip_sum = 0; + if (ipsum != checksum ((unsigned char *) &d.packet->ip, + sizeof (d.packet->ip))) + { + logger (LOG_DEBUG, "bad IP header checksum, ignoring"); + retval = -1; + goto eexit; + } + + memcpy (&source, &d.packet->ip.ip_src, sizeof (d.packet->ip.ip_src)); + memcpy (&dest, &d.packet->ip.ip_dst, sizeof (d.packet->ip.ip_dst)); + memset (&d.packet->ip, 0, sizeof (d.packet->ip)); + d.packet->udp.uh_sum = 0; + + d.packet->ip.ip_p = IPPROTO_UDP; + memcpy (&d.packet->ip.ip_src, &source, sizeof (d.packet->ip.ip_src)); + memcpy (&d.packet->ip.ip_dst, &dest, sizeof (d.packet->ip.ip_dst)); + d.packet->ip.ip_len = d.packet->udp.uh_ulen; + if (udpsum && udpsum != checksum (d.data, bytes)) + { + logger (LOG_ERR, "bad UDP checksum, ignoring"); + retval = -1; + } eexit: - d.packet->ip.ip_sum = ipsum; - d.packet->ip.ip_len = iplen; - d.packet->udp.uh_sum = udpsum; + d.packet->ip.ip_sum = ipsum; + d.packet->ip.ip_len = iplen; + d.packet->udp.uh_sum = udpsum; - return retval; + return retval; } #if defined(BSD) || defined(__FreeBSD_kernel__) int open_socket (interface_t *iface, int protocol) { - int n = 0; - int fd = -1; - char *device; - int flags; - struct ifreq ifr; - int buf = 0; - struct bpf_program pf; - - device = xmalloc (sizeof (char) * PATH_MAX); - do { - snprintf (device, PATH_MAX, "/dev/bpf%d", n++); - fd = open (device, O_RDWR); - } while (fd == -1 && errno == EBUSY); - free (device); - - if (fd == -1) { - logger (LOG_ERR, "unable to open a BPF device"); - return -1; - } - - close_on_exec (fd); - - memset (&ifr, 0, sizeof (ifr)); - strlcpy (ifr.ifr_name, iface->name, sizeof (ifr.ifr_name)); - if (ioctl (fd, BIOCSETIF, &ifr) == -1) { - logger (LOG_ERR, - "cannot attach interface `%s' to bpf device `%s': %s", - iface->name, device, strerror (errno)); - close (fd); - return -1; - } - - /* Get the required BPF buffer length from the kernel. */ - if (ioctl (fd, BIOCGBLEN, &buf) == -1) { - logger (LOG_ERR, "ioctl BIOCGBLEN: %s", strerror (errno)); - close (fd); - return -1; - } - iface->buffer_length = buf; - - flags = 1; - if (ioctl (fd, BIOCIMMEDIATE, &flags) == -1) { - logger (LOG_ERR, "ioctl BIOCIMMEDIATE: %s", strerror (errno)); - close (fd); - return -1; - } - - /* Install the DHCP filter */ - if (protocol == ETHERTYPE_ARP) { - pf.bf_insns = arp_bpf_filter; - pf.bf_len = sizeof (arp_bpf_filter) - / sizeof (arp_bpf_filter[0]); - } else { - pf.bf_insns = dhcp_bpf_filter; - pf.bf_len = sizeof (dhcp_bpf_filter) - / sizeof (dhcp_bpf_filter[0]); - } - if (ioctl (fd, BIOCSETF, &pf) == -1) { - logger (LOG_ERR, "ioctl BIOCSETF: %s", strerror (errno)); - close (fd); - return -1; - } - - if (iface->fd > -1) - close (iface->fd); - iface->fd = fd; - - return fd; + int n = 0; + int fd = -1; + char *device; + int flags; + struct ifreq ifr; + int buf = 0; + struct bpf_program pf; + + device = xmalloc (sizeof (char) * PATH_MAX); + do + { + snprintf (device, PATH_MAX, "/dev/bpf%d", n++); + fd = open (device, O_RDWR); + } + while (fd == -1 && errno == EBUSY); + free (device); + + if (fd == -1) + { + logger (LOG_ERR, "unable to open a BPF device"); + return -1; + } + + close_on_exec (fd); + + memset (&ifr, 0, sizeof (ifr)); + strlcpy (ifr.ifr_name, iface->name, sizeof (ifr.ifr_name)); + if (ioctl (fd, BIOCSETIF, &ifr) == -1) + { + logger (LOG_ERR, + "cannot attach interface `%s' to bpf device `%s': %s", + iface->name, device, strerror (errno)); + close (fd); + return -1; + } + + /* Get the required BPF buffer length from the kernel. */ + if (ioctl (fd, BIOCGBLEN, &buf) == -1) + { + logger (LOG_ERR, "ioctl BIOCGBLEN: %s", strerror (errno)); + close (fd); + return -1; + } + iface->buffer_length = buf; + + flags = 1; + if (ioctl (fd, BIOCIMMEDIATE, &flags) == -1) + { + logger (LOG_ERR, "ioctl BIOCIMMEDIATE: %s", strerror (errno)); + close (fd); + return -1; + } + + /* Install the DHCP filter */ + if (protocol == ETHERTYPE_ARP) + { + pf.bf_insns = arp_bpf_filter; + pf.bf_len = sizeof (arp_bpf_filter) + / sizeof (arp_bpf_filter[0]); + } + else + { + pf.bf_insns = dhcp_bpf_filter; + pf.bf_len = sizeof (dhcp_bpf_filter) + / sizeof (dhcp_bpf_filter[0]); + } + if (ioctl (fd, BIOCSETF, &pf) == -1) + { + logger (LOG_ERR, "ioctl BIOCSETF: %s", strerror (errno)); + close (fd); + return -1; + } + + if (iface->fd > -1) + close (iface->fd); + iface->fd = fd; + + return fd; } ssize_t send_packet (const interface_t *iface, int type, - const unsigned char *data, size_t len) + const unsigned char *data, size_t len) { - ssize_t retval = -1; - struct iovec iov[2]; - - if (iface->family == ARPHRD_ETHER) { - struct ether_header hw; - memset (&hw, 0, sizeof (hw)); - memset (&hw.ether_dhost, 0xff, ETHER_ADDR_LEN); - hw.ether_type = htons (type); - - iov[0].iov_base = &hw; - iov[0].iov_len = sizeof (hw); - } else { - logger (LOG_ERR, "unsupported interace type %d", iface->family); - return -1; - } - iov[1].iov_base = (unsigned char *) data; - iov[1].iov_len = len; - - if ((retval = writev(iface->fd, iov, 2)) == -1) - logger (LOG_ERR, "writev: %s", strerror (errno)); - - return retval; + ssize_t retval = -1; + struct iovec iov[2]; + + if (iface->family == ARPHRD_ETHER) + { + struct ether_header hw; + memset (&hw, 0, sizeof (hw)); + memset (&hw.ether_dhost, 0xff, ETHER_ADDR_LEN); + hw.ether_type = htons (type); + + iov[0].iov_base = &hw; + iov[0].iov_len = sizeof (hw); + } + else + { + logger (LOG_ERR, "unsupported interace type %d", iface->family); + return -1; + } + iov[1].iov_base = (unsigned char *) data; + iov[1].iov_len = len; + + if ((retval = writev(iface->fd, iov, 2)) == -1) + logger (LOG_ERR, "writev: %s", strerror (errno)); + + return retval; } /* BPF requires that we read the entire buffer. * So we pass the buffer in the API so we can loop on >1 dhcp packet. */ ssize_t get_packet (const interface_t *iface, unsigned char *data, - unsigned char *buffer, - size_t *buffer_len, size_t *buffer_pos) + unsigned char *buffer, + size_t *buffer_len, size_t *buffer_pos) { - union - { - unsigned char *buffer; - struct bpf_hdr *packet; - } bpf; - - bpf.buffer = buffer; - - if (*buffer_pos < 1) { - memset (bpf.buffer, 0, iface->buffer_length); - *buffer_len = read (iface->fd, bpf.buffer, iface->buffer_length); - *buffer_pos = 0; - if (*buffer_len < 1) { - struct timespec ts; - logger (LOG_ERR, "read: %s", strerror (errno)); - ts.tv_sec = 3; - ts.tv_nsec = 0; - nanosleep (&ts, NULL); - return (-1); - } - } else - bpf.buffer += *buffer_pos; - - while (bpf.packet) { - size_t len = 0; - union - { - unsigned char *buffer; - struct ether_header *hw; - } hdr; - unsigned char *payload; - bool have_data = false; - - /* Ensure that the entire packet is in our buffer */ - if (*buffer_pos + bpf.packet->bh_hdrlen + bpf.packet->bh_caplen - > (unsigned) *buffer_len) - break; - - hdr.buffer = bpf.buffer + bpf.packet->bh_hdrlen; - payload = hdr.buffer + sizeof (*hdr.hw); - - /* If it's an ARP reply, then just send it back */ - if (hdr.hw->ether_type == htons (ETHERTYPE_ARP)) { - len = bpf.packet->bh_caplen - - sizeof (*hdr.hw); - memcpy (data, payload, len); - have_data = true; - } else { - if (valid_dhcp_packet (payload) >= 0) { - union - { - unsigned char *buffer; - struct udp_dhcp_packet *packet; - } pay; - pay.buffer = payload; - len = ntohs (pay.packet->ip.ip_len) - - sizeof (pay.packet->ip) - - sizeof (pay.packet->udp); - memcpy (data, &pay.packet->dhcp, len); - have_data = true; - } - } - - /* Update the buffer_pos pointer */ - bpf.buffer += BPF_WORDALIGN (bpf.packet->bh_hdrlen + - bpf.packet->bh_caplen); - if ((unsigned) (bpf.buffer - buffer) < *buffer_len) - *buffer_pos = bpf.buffer - buffer; - else - *buffer_pos = 0; - - if (have_data) - return len; - - if (*buffer_pos == 0) - break; - } - - /* No valid packets left, so return */ - *buffer_pos = 0; - return -1; + union + { + unsigned char *buffer; + struct bpf_hdr *packet; + } bpf; + + bpf.buffer = buffer; + + if (*buffer_pos < 1) + { + memset (bpf.buffer, 0, iface->buffer_length); + *buffer_len = read (iface->fd, bpf.buffer, iface->buffer_length); + *buffer_pos = 0; + if (*buffer_len < 1) + { + struct timespec ts; + logger (LOG_ERR, "read: %s", strerror (errno)); + ts.tv_sec = 3; + ts.tv_nsec = 0; + nanosleep (&ts, NULL); + return (-1); + } + } + else + bpf.buffer += *buffer_pos; + + while (bpf.packet) + { + size_t len = 0; + union + { + unsigned char *buffer; + struct ether_header *hw; + } hdr; + unsigned char *payload; + bool have_data = false; + + /* Ensure that the entire packet is in our buffer */ + if (*buffer_pos + bpf.packet->bh_hdrlen + bpf.packet->bh_caplen + > (unsigned) *buffer_len) + break; + + hdr.buffer = bpf.buffer + bpf.packet->bh_hdrlen; + payload = hdr.buffer + sizeof (*hdr.hw); + + /* If it's an ARP reply, then just send it back */ + if (hdr.hw->ether_type == htons (ETHERTYPE_ARP)) + { + len = bpf.packet->bh_caplen - + sizeof (*hdr.hw); + memcpy (data, payload, len); + have_data = true; + } + else + { + if (valid_dhcp_packet (payload) >= 0) + { + union + { + unsigned char *buffer; + struct udp_dhcp_packet *packet; + } pay; + pay.buffer = payload; + len = ntohs (pay.packet->ip.ip_len) - + sizeof (pay.packet->ip) - + sizeof (pay.packet->udp); + memcpy (data, &pay.packet->dhcp, len); + have_data = true; + } + } + + /* Update the buffer_pos pointer */ + bpf.buffer += BPF_WORDALIGN (bpf.packet->bh_hdrlen + + bpf.packet->bh_caplen); + if ((unsigned) (bpf.buffer - buffer) < *buffer_len) + *buffer_pos = bpf.buffer - buffer; + else + *buffer_pos = 0; + + if (have_data) + return len; + + if (*buffer_pos == 0) + break; + } + + /* No valid packets left, so return */ + *buffer_pos = 0; + return -1; } #elif __linux__ int open_socket (interface_t *iface, int protocol) { - int fd; - union sockunion { - struct sockaddr sa; - struct sockaddr_in sin; - struct sockaddr_ll sll; - struct sockaddr_storage ss; - } su; - struct sock_fprog pf; - struct ifreq ifr; - int n = 1; - - /* We need to bind to a port, otherwise Linux generate ICMP messages - * that cannot contect the port when we have an address. - * We don't actually use this fd at all, instead using our packet - * filter socket. */ - if (iface->listen_fd == -1 && protocol == ETHERTYPE_IP) { - if ((fd = socket (PF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1) { - logger (LOG_ERR, "socket: %s", strerror (errno)); - } else { - memset (&su, 0, sizeof (su)); - su.sin.sin_family = AF_INET; - su.sin.sin_port = htons (DHCP_CLIENT_PORT); - if (setsockopt (fd, SOL_SOCKET, SO_REUSEADDR, - &n, sizeof (n)) == -1) - logger (LOG_ERR, "SO_REUSEADDR: %s", - strerror (errno)); - if (setsockopt (fd, SOL_SOCKET, SO_RCVBUF, - &n, sizeof (n)) == -1) - logger (LOG_ERR, "SO_RCVBUF: %s", - strerror (errno)); - memset (&ifr, 0, sizeof (ifr)); - strncpy (ifr.ifr_name, iface->name, - sizeof (ifr.ifr_name)); - if (setsockopt (fd, SOL_SOCKET, SO_BINDTODEVICE, - &ifr, sizeof (ifr)) == -1) - logger (LOG_ERR, "SO_SOBINDTODEVICE: %s", - strerror (errno)); - if (bind (fd, &su.sa, sizeof (su)) == -1) { - logger (LOG_ERR, "bind: %s", strerror (errno)); - close (fd); - } else { - iface->listen_fd = fd; - close_on_exec (fd); - } - } - } - - if ((fd = socket (PF_PACKET, SOCK_DGRAM, htons (protocol))) == -1) { - logger (LOG_ERR, "socket: %s", strerror (errno)); - return (-1); - } - close_on_exec (fd); - - memset (&su, 0, sizeof (su)); - su.sll.sll_family = PF_PACKET; - su.sll.sll_protocol = htons (protocol); - if (! (su.sll.sll_ifindex = if_nametoindex (iface->name))) { - logger (LOG_ERR, - "if_nametoindex: no index for interface `%s'", - iface->name); - close (fd); - return (-1); - } - - /* Install the DHCP filter */ - memset (&pf, 0, sizeof (pf)); - if (protocol == ETHERTYPE_ARP) { - pf.filter = arp_bpf_filter; - pf.len = sizeof (arp_bpf_filter) / sizeof (arp_bpf_filter[0]); - } else { - pf.filter = dhcp_bpf_filter; - pf.len = sizeof (dhcp_bpf_filter) / sizeof (dhcp_bpf_filter[0]); - } - if (setsockopt (fd, SOL_SOCKET, SO_ATTACH_FILTER, - &pf, sizeof (pf)) != 0) - { - logger (LOG_ERR, "SO_ATTACH_FILTER: %s", strerror (errno)); - close (fd); - return (-1); - } - - if (bind (fd, &su.sa, sizeof (su)) == -1) { - logger (LOG_ERR, "bind: %s", strerror (errno)); - close (fd); - return (-1); - } - - if (iface->fd > -1) - close (iface->fd); - iface->fd = fd; - iface->socket_protocol = protocol; - iface->buffer_length = BUFFER_LENGTH; - - return (fd); + int fd; + union sockunion + { + struct sockaddr sa; + struct sockaddr_in sin; + struct sockaddr_ll sll; + struct sockaddr_storage ss; + } su; + struct sock_fprog pf; + struct ifreq ifr; + int n = 1; + + /* We need to bind to a port, otherwise Linux generate ICMP messages + * that cannot contect the port when we have an address. + * We don't actually use this fd at all, instead using our packet + * filter socket. */ + if (iface->listen_fd == -1 && protocol == ETHERTYPE_IP) + { + if ((fd = socket (PF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1) + { + logger (LOG_ERR, "socket: %s", strerror (errno)); + } + else + { + memset (&su, 0, sizeof (su)); + su.sin.sin_family = AF_INET; + su.sin.sin_port = htons (DHCP_CLIENT_PORT); + if (setsockopt (fd, SOL_SOCKET, SO_REUSEADDR, + &n, sizeof (n)) == -1) + logger (LOG_ERR, "SO_REUSEADDR: %s", + strerror (errno)); + if (setsockopt (fd, SOL_SOCKET, SO_RCVBUF, + &n, sizeof (n)) == -1) + logger (LOG_ERR, "SO_RCVBUF: %s", + strerror (errno)); + memset (&ifr, 0, sizeof (ifr)); + strncpy (ifr.ifr_name, iface->name, + sizeof (ifr.ifr_name)); + if (setsockopt (fd, SOL_SOCKET, SO_BINDTODEVICE, + &ifr, sizeof (ifr)) == -1) + logger (LOG_ERR, "SO_SOBINDTODEVICE: %s", + strerror (errno)); + if (bind (fd, &su.sa, sizeof (su)) == -1) + { + logger (LOG_ERR, "bind: %s", strerror (errno)); + close (fd); + } + else + { + iface->listen_fd = fd; + close_on_exec (fd); + } + } + } + + if ((fd = socket (PF_PACKET, SOCK_DGRAM, htons (protocol))) == -1) + { + logger (LOG_ERR, "socket: %s", strerror (errno)); + return (-1); + } + close_on_exec (fd); + + memset (&su, 0, sizeof (su)); + su.sll.sll_family = PF_PACKET; + su.sll.sll_protocol = htons (protocol); + if (! (su.sll.sll_ifindex = if_nametoindex (iface->name))) + { + logger (LOG_ERR, + "if_nametoindex: no index for interface `%s'", + iface->name); + close (fd); + return (-1); + } + + /* Install the DHCP filter */ + memset (&pf, 0, sizeof (pf)); + if (protocol == ETHERTYPE_ARP) + { + pf.filter = arp_bpf_filter; + pf.len = sizeof (arp_bpf_filter) / sizeof (arp_bpf_filter[0]); + } + else + { + pf.filter = dhcp_bpf_filter; + pf.len = sizeof (dhcp_bpf_filter) / sizeof (dhcp_bpf_filter[0]); + } + if (setsockopt (fd, SOL_SOCKET, SO_ATTACH_FILTER, + &pf, sizeof (pf)) != 0) + { + logger (LOG_ERR, "SO_ATTACH_FILTER: %s", strerror (errno)); + close (fd); + return (-1); + } + + if (bind (fd, &su.sa, sizeof (su)) == -1) + { + logger (LOG_ERR, "bind: %s", strerror (errno)); + close (fd); + return (-1); + } + + if (iface->fd > -1) + close (iface->fd); + iface->fd = fd; + iface->socket_protocol = protocol; + iface->buffer_length = BUFFER_LENGTH; + + return (fd); } ssize_t send_packet (const interface_t *iface, int type, - const unsigned char *data, size_t len) + const unsigned char *data, size_t len) { - union sockunion { - struct sockaddr sa; - struct sockaddr_ll sll; - struct sockaddr_storage ss; - } su; - ssize_t retval; - - if (! iface) - return (-1); - - memset (&su, 0, sizeof (su)); - su.sll.sll_family = AF_PACKET; - su.sll.sll_protocol = htons (type); - - if (! (su.sll.sll_ifindex = if_nametoindex (iface->name))) { - logger (LOG_ERR, "if_nametoindex: no index for interface `%s'", - iface->name); - return (-1); - } - - su.sll.sll_hatype = htons (iface->family); - su.sll.sll_halen = iface->hwlen; - if (iface->family == ARPHRD_INFINIBAND) - memcpy (&su.sll.sll_addr, - &ipv4_bcast_addr, sizeof (ipv4_bcast_addr)); - else - memset (&su.sll.sll_addr, 0xff, iface->hwlen); - - if ((retval = sendto (iface->fd, data, len, 0, &su.sa, - sizeof (su))) == -1) - - logger (LOG_ERR, "sendto: %s", strerror (errno)); - return (retval); + union sockunion + { + struct sockaddr sa; + struct sockaddr_ll sll; + struct sockaddr_storage ss; + } su; + ssize_t retval; + + if (! iface) + return (-1); + + memset (&su, 0, sizeof (su)); + su.sll.sll_family = AF_PACKET; + su.sll.sll_protocol = htons (type); + + if (! (su.sll.sll_ifindex = if_nametoindex (iface->name))) + { + logger (LOG_ERR, "if_nametoindex: no index for interface `%s'", + iface->name); + return (-1); + } + + su.sll.sll_hatype = htons (iface->family); + su.sll.sll_halen = iface->hwlen; + if (iface->family == ARPHRD_INFINIBAND) + memcpy (&su.sll.sll_addr, + &ipv4_bcast_addr, sizeof (ipv4_bcast_addr)); + else + memset (&su.sll.sll_addr, 0xff, iface->hwlen); + + if ((retval = sendto (iface->fd, data, len, 0, &su.sa, + sizeof (su))) == -1) + + logger (LOG_ERR, "sendto: %s", strerror (errno)); + return (retval); } /* Linux has no need for the buffer as we can read as much as we want. * We only have the buffer listed to keep the same API. */ ssize_t get_packet (const interface_t *iface, unsigned char *data, - unsigned char *buffer, - size_t *buffer_len, size_t *buffer_pos) + unsigned char *buffer, + size_t *buffer_len, size_t *buffer_pos) { - ssize_t bytes; - union - { - unsigned char *buffer; - struct udp_dhcp_packet *packet; - } pay; - - /* We don't use the given buffer, but we need to rewind the position */ - *buffer_pos = 0; - - memset (buffer, 0, iface->buffer_length); - bytes = read (iface->fd, buffer, iface->buffer_length); - - if (bytes == -1) { - struct timespec ts; - logger (LOG_ERR, "read: %s", strerror (errno)); - ts.tv_sec = 3; - ts.tv_nsec = 0; - nanosleep (&ts, NULL); - return (-1); - } - - *buffer_len = bytes; - /* If it's an ARP reply, then just send it back */ - if (iface->socket_protocol == ETHERTYPE_ARP) { - memcpy (data, buffer, bytes); - return (bytes); - } - - if ((unsigned) bytes < (sizeof (pay.packet->ip) + - sizeof (pay.packet->udp))) - { - logger (LOG_DEBUG, "message too short, ignoring"); - return (-1); - } - - pay.buffer = buffer; - if (bytes < ntohs (pay.packet->ip.ip_len)) { - logger (LOG_DEBUG, "truncated packet, ignoring"); - return (-1); - } - - if (valid_dhcp_packet (buffer) == -1) - return (-1); - - bytes = ntohs (pay.packet->ip.ip_len) - - (sizeof (pay.packet->ip) + sizeof (pay.packet->udp)); - memcpy (data, &pay.packet->dhcp, bytes); - return (bytes); + ssize_t bytes; + union + { + unsigned char *buffer; + struct udp_dhcp_packet *packet; + } pay; + + /* We don't use the given buffer, but we need to rewind the position */ + *buffer_pos = 0; + + memset (buffer, 0, iface->buffer_length); + bytes = read (iface->fd, buffer, iface->buffer_length); + + if (bytes == -1) + { + struct timespec ts; + logger (LOG_ERR, "read: %s", strerror (errno)); + ts.tv_sec = 3; + ts.tv_nsec = 0; + nanosleep (&ts, NULL); + return (-1); + } + + *buffer_len = bytes; + /* If it's an ARP reply, then just send it back */ + if (iface->socket_protocol == ETHERTYPE_ARP) + { + memcpy (data, buffer, bytes); + return (bytes); + } + + if ((unsigned) bytes < (sizeof (pay.packet->ip) + + sizeof (pay.packet->udp))) + { + logger (LOG_DEBUG, "message too short, ignoring"); + return (-1); + } + + pay.buffer = buffer; + if (bytes < ntohs (pay.packet->ip.ip_len)) + { + logger (LOG_DEBUG, "truncated packet, ignoring"); + return (-1); + } + + if (valid_dhcp_packet (buffer) == -1) + return (-1); + + bytes = ntohs (pay.packet->ip.ip_len) - + (sizeof (pay.packet->ip) + sizeof (pay.packet->udp)); + memcpy (data, &pay.packet->dhcp, bytes); + return (bytes); } #else - #error "Platform not supported!" - #error "We currently support BPF and Linux sockets." - #error "Other platforms may work using BPF. If yours does, please let me know" - #error "so I can add it to our list." +#error "Platform not supported!" +#error "We currently support BPF and Linux sockets." +#error "Other platforms may work using BPF. If yours does, please let me know" +#error "so I can add it to our list." #endif |