From 22f68524f84c3a0d620e787c51d5f244ef8e0aca Mon Sep 17 00:00:00 2001 From: Joe Hershberger Date: Sun, 22 Mar 2015 17:09:23 -0500 Subject: sandbox: eth: Add support for using the 'lo' interface The 'lo' interface on Linux doesn't support thinks like ARP or link-layer access like we use to talk to a normal network interface. A higher-level network API must be used to access localhost. As written, this interface is limited to not supporting ICMP since the API doesn't allow the socket to be opened for all IP traffic and be able to receive at the same time. UDP is far more useful to test with, so it was selected over ICMP. Ping won't work, but things like TFTP should work. Signed-off-by: Joe Hershberger Reviewed-by: Simon Glass --- arch/sandbox/cpu/eth-raw-os.c | 113 +++++++++++++++++++++++++++++++++++++++++- 1 file changed, 111 insertions(+), 2 deletions(-) (limited to 'arch/sandbox/cpu') diff --git a/arch/sandbox/cpu/eth-raw-os.c b/arch/sandbox/cpu/eth-raw-os.c index 601205a60b4..b76a7319aee 100644 --- a/arch/sandbox/cpu/eth-raw-os.c +++ b/arch/sandbox/cpu/eth-raw-os.c @@ -12,6 +12,8 @@ #include #include #include +#include +#include #include #include #include @@ -20,10 +22,11 @@ #include #include +#include #include #include -int sandbox_eth_raw_os_start(const char *ifname, unsigned char *ethmac, +static int _raw_packet_start(const char *ifname, unsigned char *ethmac, struct eth_sandbox_raw_priv *priv) { struct sockaddr_ll *device; @@ -89,14 +92,114 @@ int sandbox_eth_raw_os_start(const char *ifname, unsigned char *ethmac, return 0; } +static int _local_inet_start(struct eth_sandbox_raw_priv *priv) +{ + struct sockaddr_in *device; + int ret; + int flags; + int one = 1; + + /* Prepare device struct */ + priv->device = malloc(sizeof(struct sockaddr_in)); + if (priv->device == NULL) + return -ENOMEM; + device = priv->device; + memset(device, 0, sizeof(struct sockaddr_in)); + device->sin_family = AF_INET; + device->sin_addr.s_addr = htonl(INADDR_LOOPBACK); + + /** + * Open socket + * Since we specify UDP here, any incoming ICMP packets will + * not be received, so things like ping will not work on this + * localhost interface. + */ + priv->sd = socket(AF_INET, SOCK_RAW, IPPROTO_UDP); + if (priv->sd < 0) { + printf("Failed to open socket: %d %s\n", errno, + strerror(errno)); + return -errno; + } + + /* Make the socket non-blocking */ + flags = fcntl(priv->sd, F_GETFL, 0); + fcntl(priv->sd, F_SETFL, flags | O_NONBLOCK); + + /* Include the UDP/IP headers on send and receive */ + ret = setsockopt(priv->sd, IPPROTO_IP, IP_HDRINCL, &one, + sizeof(one)); + if (ret < 0) { + printf("Failed to set header include option: %d %s\n", errno, + strerror(errno)); + return -errno; + } + priv->local_bind_sd = -1; + priv->local_bind_udp_port = 0; + return 0; +} + +int sandbox_eth_raw_os_start(const char *ifname, unsigned char *ethmac, + struct eth_sandbox_raw_priv *priv) +{ + if (priv->local) + return _local_inet_start(priv); + else + return _raw_packet_start(ifname, ethmac, priv); +} + int sandbox_eth_raw_os_send(void *packet, int length, - const struct eth_sandbox_raw_priv *priv) + struct eth_sandbox_raw_priv *priv) { int retval; + struct udphdr *udph = packet + sizeof(struct iphdr); if (!priv->sd || !priv->device) return -EINVAL; + /* + * This block of code came about when testing tftp on the localhost + * interface. When using the RAW AF_INET API, the network stack is still + * in play responding to incoming traffic based on open "ports". Since + * it is raw (at the IP layer, no Ethernet) the network stack tells the + * TFTP server that the port it responded to is closed. This causes the + * TFTP transfer to be aborted. This block of code inspects the outgoing + * packet as formulated by the u-boot network stack to determine the + * source port (that the TFTP server will send packets back to) and + * opens a typical UDP socket on that port, thus preventing the network + * stack from sending that ICMP message claiming that the port has no + * bound socket. + */ + if (priv->local && (priv->local_bind_sd == -1 || + priv->local_bind_udp_port != udph->source)) { + struct iphdr *iph = packet; + struct sockaddr_in addr; + + if (priv->local_bind_sd != -1) + close(priv->local_bind_sd); + + /* A normal UDP socket is required to bind */ + priv->local_bind_sd = socket(AF_INET, SOCK_DGRAM, 0); + if (priv->local_bind_sd < 0) { + printf("Failed to open bind sd: %d %s\n", errno, + strerror(errno)); + return -errno; + } + priv->local_bind_udp_port = udph->source; + + /** + * Bind the UDP port that we intend to use as our source port + * so that the kernel will not send an ICMP port unreachable + * message to the server + */ + addr.sin_family = AF_INET; + addr.sin_port = udph->source; + addr.sin_addr.s_addr = iph->saddr; + retval = bind(priv->local_bind_sd, &addr, sizeof(addr)); + if (retval < 0) + printf("Failed to bind: %d %s\n", errno, + strerror(errno)); + } + retval = sendto(priv->sd, packet, length, 0, (struct sockaddr *)priv->device, sizeof(struct sockaddr_ll)); @@ -137,4 +240,10 @@ void sandbox_eth_raw_os_stop(struct eth_sandbox_raw_priv *priv) priv->device = NULL; close(priv->sd); priv->sd = -1; + if (priv->local) { + if (priv->local_bind_sd != -1) + close(priv->local_bind_sd); + priv->local_bind_sd = -1; + priv->local_bind_udp_port = 0; + } } -- cgit v1.2.3