From patchwork Tue Jul 26 16:21:31 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fabien Chouteau X-Patchwork-Id: 106891 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [140.186.70.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 797C7B6F72 for ; Wed, 27 Jul 2011 02:22:01 +1000 (EST) Received: from localhost ([::1]:54752 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QlkOL-00066X-6V for incoming@patchwork.ozlabs.org; Tue, 26 Jul 2011 12:21:57 -0400 Received: from eggs.gnu.org ([140.186.70.92]:59183) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QlkOC-00064p-DZ for qemu-devel@nongnu.org; Tue, 26 Jul 2011 12:21:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QlkOA-0001ve-V4 for qemu-devel@nongnu.org; Tue, 26 Jul 2011 12:21:48 -0400 Received: from mel.act-europe.fr ([194.98.77.210]:35222) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QlkOA-0001vS-L0 for qemu-devel@nongnu.org; Tue, 26 Jul 2011 12:21:46 -0400 Received: from localhost (localhost [127.0.0.1]) by filtered-smtp.eu.adacore.com (Postfix) with ESMTP id AD990CB035C; Tue, 26 Jul 2011 18:21:45 +0200 (CEST) X-Virus-Scanned: amavisd-new at eu.adacore.com Received: from mel.act-europe.fr ([127.0.0.1]) by localhost (smtp.eu.adacore.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Xe2QhwjGcUdK; Tue, 26 Jul 2011 18:21:35 +0200 (CEST) Received: from PomPomGalli.act-europe.fr (pompomgalli.act-europe.fr [10.10.1.88]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mel.act-europe.fr (Postfix) with ESMTP id 62FECCB0310; Tue, 26 Jul 2011 18:21:35 +0200 (CEST) From: Fabien Chouteau To: qemu-devel@nongnu.org Date: Tue, 26 Jul 2011 18:21:31 +0200 Message-Id: <1311697292-9845-1-git-send-email-chouteau@adacore.com> X-Mailer: git-send-email 1.7.4.1 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 3) X-Received-From: 194.98.77.210 Cc: jan.kiszka@siemens.com Subject: [Qemu-devel] [PATCH 1/2] [SLIRP] Simple ARP table X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org This patch adds a simple ARP table in Slirp and also adds handling of gratuitous ARP requests. Signed-off-by: Fabien Chouteau --- Makefile.objs | 2 +- slirp/arp_table.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++ slirp/bootp.c | 15 ++++++----- slirp/slirp.c | 68 ++++++++++++++++------------------------------------ slirp/slirp.h | 51 +++++++++++++++++++++++++++++++++++++-- 5 files changed, 139 insertions(+), 58 deletions(-) create mode 100644 slirp/arp_table.c diff --git a/Makefile.objs b/Makefile.objs index 6991a9f..0c10557 100644 --- a/Makefile.objs +++ b/Makefile.objs @@ -151,7 +151,7 @@ common-obj-y += qemu-timer.o qemu-timer-common.o slirp-obj-y = cksum.o if.o ip_icmp.o ip_input.o ip_output.o slirp-obj-y += slirp.o mbuf.o misc.o sbuf.o socket.o tcp_input.o tcp_output.o -slirp-obj-y += tcp_subr.o tcp_timer.o udp.o bootp.o tftp.o +slirp-obj-y += tcp_subr.o tcp_timer.o udp.o bootp.o tftp.o arp_table.o common-obj-$(CONFIG_SLIRP) += $(addprefix slirp/, $(slirp-obj-y)) # xen backend driver support diff --git a/slirp/arp_table.c b/slirp/arp_table.c new file mode 100644 index 0000000..e3251ed --- /dev/null +++ b/slirp/arp_table.c @@ -0,0 +1,61 @@ +#include "slirp.h" + +void arp_table_flush(ArpTable *arptbl) +{ + int i; + + assert(arptbl != NULL); + + for (i = 0; i < ARP_TABLE_SIZE; i++) { + arptbl->table[i].ar_sip = 0; + } + arptbl->next_victim = 0; +} + +void arp_table_add(ArpTable *arptbl, + struct arphdr *ahdr) +{ + int i; + + DEBUG_CALL("arp_table_add"); + DEBUG_ARG("ip = 0x%x", ahdr->ar_sip); + DEBUG_ARGS((dfd, " hw addr = %02x:%02x:%02x:%02x:%02x:%02x\n", + ahdr->ar_sha[0], ahdr->ar_sha[1], ahdr->ar_sha[2], + ahdr->ar_sha[3], ahdr->ar_sha[4], ahdr->ar_sha[5])); + + /* Search for an entry */ + for (i = 0; i < ARP_TABLE_SIZE && arptbl->table[i].ar_sip != 0; i++) { + if (arptbl->table[i].ar_sip == ahdr->ar_sip) { + /* Update the entry */ + memcpy(arptbl->table[i].ar_sha, ahdr->ar_sha, ETH_ALEN); + return; + } + } + + /* No entry found, create a new one */ + arptbl->table[arptbl->next_victim].ar_sip = ahdr->ar_sip; + memcpy(arptbl->table[arptbl->next_victim].ar_sha, ahdr->ar_sha, ETH_ALEN); + arptbl->next_victim = (arptbl->next_victim + 1) % ARP_TABLE_SIZE; +} + +bool arp_table_search(ArpTable *arptbl, + int in_ip_addr, + uint8_t out_ethaddr[ETH_ALEN]) +{ + int i; + + DEBUG_CALL("arp_table_search"); + DEBUG_ARG("ip = 0x%x", in_ip_addr); + + for (i = 0; i < ARP_TABLE_SIZE; i++) { + if (arptbl->table[i].ar_sip == in_ip_addr) { + memcpy(out_ethaddr, arptbl->table[i].ar_sha, ETH_ALEN); + DEBUG_ARGS((dfd, " found hw addr = %02x:%02x:%02x:%02x:%02x:%02x\n", + out_ethaddr[0], out_ethaddr[1], out_ethaddr[2], + out_ethaddr[3], out_ethaddr[4], out_ethaddr[5])); + return 1; + } + } + + return 0; +} diff --git a/slirp/bootp.c b/slirp/bootp.c index 1eb2ed1..ccca93b 100644 --- a/slirp/bootp.c +++ b/slirp/bootp.c @@ -149,6 +149,7 @@ static void bootp_reply(Slirp *slirp, const struct bootp_t *bp) struct in_addr preq_addr; int dhcp_msg_type, val; uint8_t *q; + uint8_t client_ethaddr[ETH_ALEN]; /* extract exact DHCP msg type */ dhcp_decode(bp, &dhcp_msg_type, &preq_addr); @@ -165,7 +166,7 @@ static void bootp_reply(Slirp *slirp, const struct bootp_t *bp) dhcp_msg_type != DHCPREQUEST) return; /* XXX: this is a hack to get the client mac address */ - memcpy(slirp->client_ethaddr, bp->bp_hwaddr, 6); + memcpy(client_ethaddr, bp->bp_hwaddr, ETH_ALEN); m = m_get(slirp); if (!m) { @@ -178,25 +179,25 @@ static void bootp_reply(Slirp *slirp, const struct bootp_t *bp) if (dhcp_msg_type == DHCPDISCOVER) { if (preq_addr.s_addr != htonl(0L)) { - bc = request_addr(slirp, &preq_addr, slirp->client_ethaddr); + bc = request_addr(slirp, &preq_addr, client_ethaddr); if (bc) { daddr.sin_addr = preq_addr; } } if (!bc) { new_addr: - bc = get_new_addr(slirp, &daddr.sin_addr, slirp->client_ethaddr); + bc = get_new_addr(slirp, &daddr.sin_addr, client_ethaddr); if (!bc) { DPRINTF("no address left\n"); return; } } - memcpy(bc->macaddr, slirp->client_ethaddr, 6); + memcpy(bc->macaddr, client_ethaddr, ETH_ALEN); } else if (preq_addr.s_addr != htonl(0L)) { - bc = request_addr(slirp, &preq_addr, slirp->client_ethaddr); + bc = request_addr(slirp, &preq_addr, client_ethaddr); if (bc) { daddr.sin_addr = preq_addr; - memcpy(bc->macaddr, slirp->client_ethaddr, 6); + memcpy(bc->macaddr, client_ethaddr, ETH_ALEN); } else { daddr.sin_addr.s_addr = 0; } @@ -218,7 +219,7 @@ static void bootp_reply(Slirp *slirp, const struct bootp_t *bp) rbp->bp_xid = bp->bp_xid; rbp->bp_htype = 1; rbp->bp_hlen = 6; - memcpy(rbp->bp_hwaddr, bp->bp_hwaddr, 6); + memcpy(rbp->bp_hwaddr, bp->bp_hwaddr, ETH_ALEN); rbp->bp_yiaddr = daddr.sin_addr; /* Client IP address */ rbp->bp_siaddr = saddr.sin_addr; /* Server IP address */ diff --git a/slirp/slirp.c b/slirp/slirp.c index df787ea..29966e6 100644 --- a/slirp/slirp.c +++ b/slirp/slirp.c @@ -31,11 +31,11 @@ struct in_addr loopback_addr; /* emulated hosts use the MAC addr 52:55:IP:IP:IP:IP */ -static const uint8_t special_ethaddr[6] = { +static const uint8_t special_ethaddr[ETH_ALEN] = { 0x52, 0x55, 0x00, 0x00, 0x00, 0x00 }; -static const uint8_t zero_ethaddr[6] = { 0, 0, 0, 0, 0, 0 }; +static const uint8_t zero_ethaddr[ETH_ALEN] = { 0, 0, 0, 0, 0, 0 }; /* XXX: suppress those select globals */ fd_set *global_readfds, *global_writefds, *global_xfds; @@ -237,6 +237,8 @@ Slirp *slirp_init(int restricted, struct in_addr vnetwork, QTAILQ_INSERT_TAIL(&slirp_instances, slirp, entry); + arp_table_flush(&slirp->arp_table); + return slirp; } @@ -599,42 +601,8 @@ void slirp_select_poll(fd_set *readfds, fd_set *writefds, fd_set *xfds, global_xfds = NULL; } -#define ETH_ALEN 6 -#define ETH_HLEN 14 - -#define ETH_P_IP 0x0800 /* Internet Protocol packet */ -#define ETH_P_ARP 0x0806 /* Address Resolution packet */ - -#define ARPOP_REQUEST 1 /* ARP request */ -#define ARPOP_REPLY 2 /* ARP reply */ - -struct ethhdr -{ - unsigned char h_dest[ETH_ALEN]; /* destination eth addr */ - unsigned char h_source[ETH_ALEN]; /* source ether addr */ - unsigned short h_proto; /* packet type ID field */ -}; - -struct arphdr -{ - unsigned short ar_hrd; /* format of hardware address */ - unsigned short ar_pro; /* format of protocol address */ - unsigned char ar_hln; /* length of hardware address */ - unsigned char ar_pln; /* length of protocol address */ - unsigned short ar_op; /* ARP opcode (command) */ - - /* - * Ethernet looks like this : This bit is variable sized however... - */ - unsigned char ar_sha[ETH_ALEN]; /* sender hardware address */ - uint32_t ar_sip; /* sender IP address */ - unsigned char ar_tha[ETH_ALEN]; /* target hardware address */ - uint32_t ar_tip ; /* target IP address */ -} __attribute__((packed)); - static void arp_input(Slirp *slirp, const uint8_t *pkt, int pkt_len) { - struct ethhdr *eh = (struct ethhdr *)pkt; struct arphdr *ah = (struct arphdr *)(pkt + ETH_HLEN); uint8_t arp_reply[max(ETH_HLEN + sizeof(struct arphdr), 64)]; struct ethhdr *reh = (struct ethhdr *)arp_reply; @@ -645,6 +613,13 @@ static void arp_input(Slirp *slirp, const uint8_t *pkt, int pkt_len) ar_op = ntohs(ah->ar_op); switch(ar_op) { case ARPOP_REQUEST: + + if (ah->ar_tip == ah->ar_sip) { + /* Gratuitous ARP */ + arp_table_add(&slirp->arp_table, ah); + return; + } + if ((ah->ar_tip & slirp->vnetwork_mask.s_addr) == slirp->vnetwork_addr.s_addr) { if (ah->ar_tip == slirp->vnameserver_addr.s_addr || @@ -657,8 +632,7 @@ static void arp_input(Slirp *slirp, const uint8_t *pkt, int pkt_len) return; arp_ok: memset(arp_reply, 0, sizeof(arp_reply)); - /* XXX: make an ARP request to have the client address */ - memcpy(slirp->client_ethaddr, eh->h_source, ETH_ALEN); + arp_table_add(&slirp->arp_table, ah); /* ARP request for alias/dns mac address */ memcpy(reh->h_dest, pkt + ETH_ALEN, ETH_ALEN); @@ -677,13 +651,11 @@ static void arp_input(Slirp *slirp, const uint8_t *pkt, int pkt_len) rah->ar_tip = ah->ar_sip; slirp_output(slirp->opaque, arp_reply, sizeof(arp_reply)); } + + break; case ARPOP_REPLY: - /* reply to request of client mac address ? */ - if (!memcmp(slirp->client_ethaddr, zero_ethaddr, ETH_ALEN) && - ah->ar_sip == slirp->client_ipaddr.s_addr) { - memcpy(slirp->client_ethaddr, ah->ar_sha, ETH_ALEN); - } + arp_table_add(&slirp->arp_table, ah); break; default: break; @@ -729,15 +701,16 @@ void if_encap(Slirp *slirp, const uint8_t *ip_data, int ip_data_len) { uint8_t buf[1600]; struct ethhdr *eh = (struct ethhdr *)buf; + uint8_t ethaddr[ETH_ALEN]; + const struct ip *iph = (const struct ip *)ip_data; if (ip_data_len + ETH_HLEN > sizeof(buf)) return; - - if (!memcmp(slirp->client_ethaddr, zero_ethaddr, ETH_ALEN)) { + + if (!arp_table_search(&slirp->arp_table, iph->ip_dst.s_addr, ethaddr)) { uint8_t arp_req[ETH_HLEN + sizeof(struct arphdr)]; struct ethhdr *reh = (struct ethhdr *)arp_req; struct arphdr *rah = (struct arphdr *)(arp_req + ETH_HLEN); - const struct ip *iph = (const struct ip *)ip_data; /* If the client addr is not known, there is no point in sending the packet to it. Normally the sender should have @@ -764,8 +737,9 @@ void if_encap(Slirp *slirp, const uint8_t *ip_data, int ip_data_len) rah->ar_tip = iph->ip_dst.s_addr; slirp->client_ipaddr = iph->ip_dst; slirp_output(slirp->opaque, arp_req, sizeof(arp_req)); + } else { - memcpy(eh->h_dest, slirp->client_ethaddr, ETH_ALEN); + memcpy(eh->h_dest, ethaddr, ETH_ALEN); memcpy(eh->h_source, special_ethaddr, ETH_ALEN - 4); /* XXX: not correct */ memcpy(&eh->h_source[2], &slirp->vhost_addr, 4); diff --git a/slirp/slirp.h b/slirp/slirp.h index 16bb6ba..13d7471 100644 --- a/slirp/slirp.h +++ b/slirp/slirp.h @@ -170,6 +170,52 @@ int inet_aton(const char *cp, struct in_addr *ia); /* osdep.c */ int qemu_socket(int domain, int type, int protocol); +#define ETH_ALEN 6 +#define ETH_HLEN 14 + +#define ETH_P_IP 0x0800 /* Internet Protocol packet */ +#define ETH_P_ARP 0x0806 /* Address Resolution packet */ + +#define ARPOP_REQUEST 1 /* ARP request */ +#define ARPOP_REPLY 2 /* ARP reply */ + +struct ethhdr { + unsigned char h_dest[ETH_ALEN]; /* destination eth addr */ + unsigned char h_source[ETH_ALEN]; /* source ether addr */ + unsigned short h_proto; /* packet type ID field */ +}; + +struct arphdr { + unsigned short ar_hrd; /* format of hardware address */ + unsigned short ar_pro; /* format of protocol address */ + unsigned char ar_hln; /* length of hardware address */ + unsigned char ar_pln; /* length of protocol address */ + unsigned short ar_op; /* ARP opcode (command) */ + + /* + * Ethernet looks like this : This bit is variable sized however... + */ + unsigned char ar_sha[ETH_ALEN]; /* sender hardware address */ + uint32_t ar_sip; /* sender IP address */ + unsigned char ar_tha[ETH_ALEN]; /* target hardware address */ + uint32_t ar_tip; /* target IP address */ +} __attribute__((packed)); + +#define ARP_TABLE_SIZE 16 + +typedef struct ArpTable { + struct arphdr table[ARP_TABLE_SIZE]; + int next_victim; +} ArpTable; + +void arp_table_flush(ArpTable *arptbl); + +void arp_table_add(ArpTable *arptbl, + struct arphdr *ahdr); + +bool arp_table_search(ArpTable *arptbl, + int in_ip_addr, + uint8_t out_ethaddr[ETH_ALEN]); struct Slirp { QTAILQ_ENTRY(Slirp) entry; @@ -181,9 +227,6 @@ struct Slirp { struct in_addr vdhcp_startaddr; struct in_addr vnameserver_addr; - /* ARP cache for the guest IP addresses (XXX: allow many entries) */ - uint8_t client_ethaddr[6]; - struct in_addr client_ipaddr; char client_hostname[33]; @@ -227,6 +270,8 @@ struct Slirp { char *tftp_prefix; struct tftp_session tftp_sessions[TFTP_SESSIONS_MAX]; + ArpTable arp_table; + void *opaque; };