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slirp: Add IPv6 support to the TFTP code
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Add the handler code for incoming TFTP packets to udp6_input(),
and make sure that the TFTP code can send packets with both,
udp_output() and udp6_output() by introducing a wrapper function
called tftp_udp_output().

Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
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@huth @sthibaul
huth authored and sthibaul committed Mar 15, 2016
1 parent 7aac531 commit fad7fb9
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Showing 4 changed files with 100 additions and 72 deletions.
133 changes: 74 additions & 59 deletions slirp/tftp.c
View file
Expand Up @@ -46,7 +46,8 @@ static void tftp_session_terminate(struct tftp_session *spt)
spt->slirp = NULL;
}

static int tftp_session_allocate(Slirp *slirp, struct tftp_t *tp)
static int tftp_session_allocate(Slirp *slirp, struct sockaddr_storage *srcsas,
struct tftp_t *tp)
{
struct tftp_session *spt;
int k;
Expand All @@ -68,7 +69,7 @@ static int tftp_session_allocate(Slirp *slirp, struct tftp_t *tp)

found:
memset(spt, 0, sizeof(*spt));
memcpy(&spt->client_ip, &tp->ip.ip_src, sizeof(spt->client_ip));
spt->client_addr = *srcsas;
spt->fd = -1;
spt->client_port = tp->udp.uh_sport;
spt->slirp = slirp;
Expand All @@ -78,7 +79,8 @@ static int tftp_session_allocate(Slirp *slirp, struct tftp_t *tp)
return k;
}

static int tftp_session_find(Slirp *slirp, struct tftp_t *tp)
static int tftp_session_find(Slirp *slirp, struct sockaddr_storage *srcsas,
struct tftp_t *tp)
{
struct tftp_session *spt;
int k;
Expand All @@ -87,7 +89,7 @@ static int tftp_session_find(Slirp *slirp, struct tftp_t *tp)
spt = &slirp->tftp_sessions[k];

if (tftp_session_in_use(spt)) {
if (!memcmp(&spt->client_ip, &tp->ip.ip_src, sizeof(spt->client_ip))) {
if (sockaddr_equal(&spt->client_addr, srcsas)) {
if (spt->client_port == tp->udp.uh_sport) {
return k;
}
Expand Down Expand Up @@ -120,25 +122,63 @@ static int tftp_read_data(struct tftp_session *spt, uint32_t block_nr,
return bytes_read;
}

static struct tftp_t *tftp_prep_mbuf_data(struct tftp_session *spt,
struct mbuf *m)
{
struct tftp_t *tp;

memset(m->m_data, 0, m->m_size);

m->m_data += IF_MAXLINKHDR;
if (spt->client_addr.ss_family == AF_INET6) {
m->m_data += sizeof(struct ip6);
} else {
m->m_data += sizeof(struct ip);
}
tp = (void *)m->m_data;
m->m_data += sizeof(struct udphdr);

return tp;
}

static void tftp_udp_output(struct tftp_session *spt, struct mbuf *m,
struct tftp_t *recv_tp)
{
if (spt->client_addr.ss_family == AF_INET6) {
struct sockaddr_in6 sa6, da6;

sa6.sin6_addr = spt->slirp->vhost_addr6;
sa6.sin6_port = recv_tp->udp.uh_dport;
da6.sin6_addr = ((struct sockaddr_in6 *)&spt->client_addr)->sin6_addr;
da6.sin6_port = spt->client_port;

udp6_output(NULL, m, &sa6, &da6);
} else {
struct sockaddr_in sa4, da4;

sa4.sin_addr = spt->slirp->vhost_addr;
sa4.sin_port = recv_tp->udp.uh_dport;
da4.sin_addr = ((struct sockaddr_in *)&spt->client_addr)->sin_addr;
da4.sin_port = spt->client_port;

udp_output(NULL, m, &sa4, &da4, IPTOS_LOWDELAY);
}
}

static int tftp_send_oack(struct tftp_session *spt,
const char *keys[], uint32_t values[], int nb,
struct tftp_t *recv_tp)
{
struct sockaddr_in saddr, daddr;
struct mbuf *m;
struct tftp_t *tp;
int i, n = 0;

m = m_get(spt->slirp);

if (!m)
return -1;

memset(m->m_data, 0, m->m_size);
return -1;

m->m_data += IF_MAXLINKHDR;
tp = (void *)m->m_data;
m->m_data += sizeof(struct udpiphdr);
tp = tftp_prep_mbuf_data(spt, m);

tp->tp_op = htons(TFTP_OACK);
for (i = 0; i < nb; i++) {
Expand All @@ -148,15 +188,8 @@ static int tftp_send_oack(struct tftp_session *spt,
values[i]) + 1;
}

saddr.sin_addr = recv_tp->ip.ip_dst;
saddr.sin_port = recv_tp->udp.uh_dport;

daddr.sin_addr = spt->client_ip;
daddr.sin_port = spt->client_port;

m->m_len = sizeof(struct tftp_t) - 514 + n -
sizeof(struct ip) - sizeof(struct udphdr);
udp_output(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
m->m_len = sizeof(struct tftp_t) - 514 + n - sizeof(struct udphdr);
tftp_udp_output(spt, m, recv_tp);

return 0;
}
Expand All @@ -165,7 +198,6 @@ static void tftp_send_error(struct tftp_session *spt,
uint16_t errorcode, const char *msg,
struct tftp_t *recv_tp)
{
struct sockaddr_in saddr, daddr;
struct mbuf *m;
struct tftp_t *tp;

Expand All @@ -177,24 +209,15 @@ static void tftp_send_error(struct tftp_session *spt,

memset(m->m_data, 0, m->m_size);

m->m_data += IF_MAXLINKHDR;
tp = (void *)m->m_data;
m->m_data += sizeof(struct udpiphdr);
tp = tftp_prep_mbuf_data(spt, m);

tp->tp_op = htons(TFTP_ERROR);
tp->x.tp_error.tp_error_code = htons(errorcode);
pstrcpy((char *)tp->x.tp_error.tp_msg, sizeof(tp->x.tp_error.tp_msg), msg);

saddr.sin_addr = recv_tp->ip.ip_dst;
saddr.sin_port = recv_tp->udp.uh_dport;

daddr.sin_addr = spt->client_ip;
daddr.sin_port = spt->client_port;

m->m_len = sizeof(struct tftp_t) - 514 + 3 + strlen(msg) -
sizeof(struct ip) - sizeof(struct udphdr);

udp_output(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
m->m_len = sizeof(struct tftp_t) - 514 + 3 + strlen(msg)
- sizeof(struct udphdr);
tftp_udp_output(spt, m, recv_tp);

out:
tftp_session_terminate(spt);
Expand All @@ -203,7 +226,6 @@ static void tftp_send_error(struct tftp_session *spt,
static void tftp_send_next_block(struct tftp_session *spt,
struct tftp_t *recv_tp)
{
struct sockaddr_in saddr, daddr;
struct mbuf *m;
struct tftp_t *tp;
int nobytes;
Expand All @@ -216,19 +238,11 @@ static void tftp_send_next_block(struct tftp_session *spt,

memset(m->m_data, 0, m->m_size);

m->m_data += IF_MAXLINKHDR;
tp = (void *)m->m_data;
m->m_data += sizeof(struct udpiphdr);
tp = tftp_prep_mbuf_data(spt, m);

tp->tp_op = htons(TFTP_DATA);
tp->x.tp_data.tp_block_nr = htons((spt->block_nr + 1) & 0xffff);

saddr.sin_addr = recv_tp->ip.ip_dst;
saddr.sin_port = recv_tp->udp.uh_dport;

daddr.sin_addr = spt->client_ip;
daddr.sin_port = spt->client_port;

nobytes = tftp_read_data(spt, spt->block_nr, tp->x.tp_data.tp_buf, 512);

if (nobytes < 0) {
Expand All @@ -241,10 +255,8 @@ static void tftp_send_next_block(struct tftp_session *spt,
return;
}

m->m_len = sizeof(struct tftp_t) - (512 - nobytes) -
sizeof(struct ip) - sizeof(struct udphdr);

udp_output(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
m->m_len = sizeof(struct tftp_t) - (512 - nobytes) - sizeof(struct udphdr);
tftp_udp_output(spt, m, recv_tp);

if (nobytes == 512) {
tftp_session_update(spt);
Expand All @@ -256,7 +268,8 @@ static void tftp_send_next_block(struct tftp_session *spt,
spt->block_nr++;
}

static void tftp_handle_rrq(Slirp *slirp, struct tftp_t *tp, int pktlen)
static void tftp_handle_rrq(Slirp *slirp, struct sockaddr_storage *srcsas,
struct tftp_t *tp, int pktlen)
{
struct tftp_session *spt;
int s, k;
Expand All @@ -267,12 +280,12 @@ static void tftp_handle_rrq(Slirp *slirp, struct tftp_t *tp, int pktlen)
int nb_options = 0;

/* check if a session already exists and if so terminate it */
s = tftp_session_find(slirp, tp);
s = tftp_session_find(slirp, srcsas, tp);
if (s >= 0) {
tftp_session_terminate(&slirp->tftp_sessions[s]);
}

s = tftp_session_allocate(slirp, tp);
s = tftp_session_allocate(slirp, srcsas, tp);

if (s < 0) {
return;
Expand Down Expand Up @@ -397,11 +410,12 @@ static void tftp_handle_rrq(Slirp *slirp, struct tftp_t *tp, int pktlen)
tftp_send_next_block(spt, tp);
}

static void tftp_handle_ack(Slirp *slirp, struct tftp_t *tp, int pktlen)
static void tftp_handle_ack(Slirp *slirp, struct sockaddr_storage *srcsas,
struct tftp_t *tp, int pktlen)
{
int s;

s = tftp_session_find(slirp, tp);
s = tftp_session_find(slirp, srcsas, tp);

if (s < 0) {
return;
Expand All @@ -410,11 +424,12 @@ static void tftp_handle_ack(Slirp *slirp, struct tftp_t *tp, int pktlen)
tftp_send_next_block(&slirp->tftp_sessions[s], tp);
}

static void tftp_handle_error(Slirp *slirp, struct tftp_t *tp, int pktlen)
static void tftp_handle_error(Slirp *slirp, struct sockaddr_storage *srcsas,
struct tftp_t *tp, int pktlen)
{
int s;

s = tftp_session_find(slirp, tp);
s = tftp_session_find(slirp, srcsas, tp);

if (s < 0) {
return;
Expand All @@ -423,21 +438,21 @@ static void tftp_handle_error(Slirp *slirp, struct tftp_t *tp, int pktlen)
tftp_session_terminate(&slirp->tftp_sessions[s]);
}

void tftp_input(struct mbuf *m)
void tftp_input(struct sockaddr_storage *srcsas, struct mbuf *m)
{
struct tftp_t *tp = (struct tftp_t *)m->m_data;

switch(ntohs(tp->tp_op)) {
case TFTP_RRQ:
tftp_handle_rrq(m->slirp, tp, m->m_len);
tftp_handle_rrq(m->slirp, srcsas, tp, m->m_len);
break;

case TFTP_ACK:
tftp_handle_ack(m->slirp, tp, m->m_len);
tftp_handle_ack(m->slirp, srcsas, tp, m->m_len);
break;

case TFTP_ERROR:
tftp_handle_error(m->slirp, tp, m->m_len);
tftp_handle_error(m->slirp, srcsas, tp, m->m_len);
break;
}
}
7 changes: 3 additions & 4 deletions slirp/tftp.h
View file
Expand Up @@ -16,7 +16,6 @@
#define TFTP_FILENAME_MAX 512

struct tftp_t {
struct ip ip;
struct udphdr udp;
uint16_t tp_op;
union {
Expand All @@ -30,20 +29,20 @@ struct tftp_t {
} tp_error;
char tp_buf[512 + 2];
} x;
};
} __attribute__((packed));

struct tftp_session {
Slirp *slirp;
char *filename;
int fd;

struct in_addr client_ip;
struct sockaddr_storage client_addr;
uint16_t client_port;
uint32_t block_nr;

int timestamp;
};

void tftp_input(struct mbuf *m);
void tftp_input(struct sockaddr_storage *srcsas, struct mbuf *m);

#endif
16 changes: 10 additions & 6 deletions slirp/udp.c
View file
Expand Up @@ -128,6 +128,11 @@ udp_input(register struct mbuf *m, int iphlen)
}
}

lhost.ss_family = AF_INET;
lhost4 = (struct sockaddr_in *) &lhost;
lhost4->sin_addr = ip->ip_src;
lhost4->sin_port = uh->uh_sport;

/*
* handle DHCP/BOOTP
*/
Expand All @@ -143,7 +148,11 @@ udp_input(register struct mbuf *m, int iphlen)
*/
if (ntohs(uh->uh_dport) == TFTP_SERVER &&
ip->ip_dst.s_addr == slirp->vhost_addr.s_addr) {
tftp_input(m);
m->m_data += iphlen;
m->m_len -= iphlen;
tftp_input(&lhost, m);
m->m_data -= iphlen;
m->m_len += iphlen;
goto bad;
}

Expand All @@ -154,11 +163,6 @@ udp_input(register struct mbuf *m, int iphlen)
/*
* Locate pcb for datagram.
*/
lhost.ss_family = AF_INET;
lhost4 = (struct sockaddr_in *) &lhost;
lhost4->sin_addr = ip->ip_src;
lhost4->sin_port = uh->uh_sport;

so = solookup(&slirp->udp_last_so, &slirp->udb, &lhost, NULL);

if (so == NULL) {
Expand Down
16 changes: 13 additions & 3 deletions slirp/udp6.c
View file
Expand Up @@ -57,14 +57,24 @@ void udp6_input(struct mbuf *m)
*/
save_ip = *ip;

/* TODO handle DHCP/BOOTP */
/* TODO handle TFTP */

/* Locate pcb for datagram. */
lhost.sin6_family = AF_INET6;
lhost.sin6_addr = ip->ip_src;
lhost.sin6_port = uh->uh_sport;

/* TODO handle DHCP/BOOTP */

/* handle TFTP */
if (ntohs(uh->uh_dport) == TFTP_SERVER &&
!memcmp(ip->ip_dst.s6_addr, slirp->vhost_addr6.s6_addr, 16)) {
m->m_data += iphlen;
m->m_len -= iphlen;
tftp_input((struct sockaddr_storage *)&lhost, m);
m->m_data -= iphlen;
m->m_len += iphlen;
goto bad;
}

so = solookup(&slirp->udp_last_so, &slirp->udb,
(struct sockaddr_storage *) &lhost, NULL);

Expand Down

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