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fix(incoming): treat GRANT offset as unsigned in homa_grant_pkt #99

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fix(incoming): treat GRANT offset as unsigned in homa_grant_pkt #99

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10 changes: 4 additions & 6 deletions homa_incoming.c
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Original file line number Diff line number Diff line change
Expand Up @@ -806,17 +806,15 @@ void homa_grant_pkt(struct sk_buff *skb, struct homa_rpc *rpc)
__must_hold(rpc->bucket->lock)
{
struct homa_grant_hdr *h = (struct homa_grant_hdr *)skb->data;
int new_offset = ntohl(h->offset);
u32 new_offset = ntohl(h->offset);

tt_record4("processing grant for id %llu, offset %d, priority %d, increment %d",
homa_local_id(h->common.sender_id), ntohl(h->offset),
h->priority, new_offset - rpc->msgout.granted);
if (rpc->state == RPC_OUTGOING) {
if (new_offset > rpc->msgout.granted) {
rpc->msgout.granted = new_offset;
if (new_offset > rpc->msgout.length)
rpc->msgout.granted = rpc->msgout.length;
}
if (new_offset > rpc->msgout.granted)
rpc->msgout.granted = min_t(u32, new_offset,
rpc->msgout.length);
rpc->msgout.sched_priority = h->priority;
homa_xmit_data(rpc);
}
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44 changes: 44 additions & 0 deletions test/unit_homa_incoming.c
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Expand Up @@ -1874,6 +1874,50 @@ TEST_F(homa_incoming, homa_grant_pkt__grant_past_end_of_message)
&h.common, 0, 0));
EXPECT_EQ(20000, crpc->msgout.granted);
}
TEST_F(homa_incoming, homa_grant_pkt__offset_is_unsigned)
{
/* A GRANT's offset is an unsigned wire field. Reading it into a signed
* int makes an offset with the top bit set (>= 2GB) negative, so the
* "new_offset > granted" test fails and the grant is silently dropped
* instead of being clamped to the message length. Treat it as u32 so
* the existing >granted / clamp-to-length logic bounds it correctly.
*
* Table-driven: each row is a grant offset and the granted value it
* should produce for a 20000-byte outgoing message.
*/
struct homa_rpc *crpc = unit_client_rpc(&self->hsk,
UNIT_OUTGOING, self->client_ip, self->server_ip,
self->server_port, self->client_id, 20000, 1600);
static const struct {
const char *name;
u32 offset;
int exp_granted;
} cases[] = {
{"normal_grant_advances", 12000, 12000},
{"grant_past_end_clamps_to_length", 25000, 20000},
{"high_bit_offset_clamps_not_ignored", 0x80000000, 20000},
};
int i;

ASSERT_NE(NULL, crpc);
for (i = 0; i < (int)ARRAY_SIZE(cases); i++) {
struct homa_grant_hdr h = {{.sport = htons(self->server_port),
.dport = htons(self->hsk.port),
.sender_id = cpu_to_be64(self->server_id),
.type = GRANT},
.offset = htonl(cases[i].offset),
.priority = 3};

TH_LOG("case: %s", cases[i].name);
crpc->state = RPC_OUTGOING;
crpc->msgout.granted = 5000;
unit_log_clear();
homa_dispatch_pkts(mock_skb_alloc(self->client_ip,
self->server_ip,
&h.common, 0, 0));
EXPECT_EQ(cases[i].exp_granted, crpc->msgout.granted);
}
}
#endif /* See strip.py */

TEST_F(homa_incoming, homa_resend_pkt__unknown_rpc)
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