Message ID | 1311697292-9845-1-git-send-email-chouteau@adacore.com |
---|---|
State | New |
Headers | show |
On 2011-07-26 18:21, Fabien Chouteau wrote: > This patch adds a simple ARP table in Slirp and also adds handling of > gratuitous ARP requests. > > Signed-off-by: Fabien Chouteau <chouteau@adacore.com> > --- > 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; > +} arp_table_flush is only used for initialization, but the memory it touches is already zero-initialized (on alloc in slirp_init). So you can save this service. > + > +void arp_table_add(ArpTable *arptbl, > + struct arphdr *ahdr) Let's stick with void arp_table_add(ArpTable *arptbl, struct arphdr *ahdr) formatting. That's more consistent with other parts of QEMU. > +{ > + 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; Pragmatic aging. But I guess that's OK, we shouldn't need anything smarter here. > +} > + > +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); Makes me wonder if the comment above still applies. > > 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: > + Please drop this blank line. > + 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)); > } > + > + Spurious empty lines. > 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)); > + ...and another one. > } 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; > }; > > -- > 1.7.4.1 > Looks good otherwise. Jan
On 27/07/2011 12:49, Jan Kiszka wrote: > On 2011-07-26 18:21, Fabien Chouteau wrote: >> This patch adds a simple ARP table in Slirp and also adds handling of >> gratuitous ARP requests. >> >> Signed-off-by: Fabien Chouteau <chouteau@adacore.com> >> --- >> 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; >> +} > > arp_table_flush is only used for initialization, but the memory it > touches is already zero-initialized (on alloc in slirp_init). So you can > save this service. OK, it was just in case slirp can be re-initialized. >> +{ >> + 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; > > Pragmatic aging. But I guess that's OK, we shouldn't need anything > smarter here. Yes, simple round-robin. >> 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); > > Makes me wonder if the comment above still applies. Actually I don't think it is a hack at all. Makes me think I should update the ARP table here, with the IP address assigned to this client. Thanks for your review, I will fix the others style problems. Regards,
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; };
This patch adds a simple ARP table in Slirp and also adds handling of gratuitous ARP requests. Signed-off-by: Fabien Chouteau <chouteau@adacore.com> --- 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