From 7a838c8798a93fc4b0eb305c4c7d61da54875a14 Mon Sep 17 00:00:00 2001 From: Chas Williams Date: Mon, 26 Nov 2018 23:56:13 -0500 Subject: [PATCH] ip_frag: fix IPv6 when MTU sizes not aligned to 8 bytes The same issue was fixed on for the ipv4 version of this routine in commit 8d4d3a4f7337 ("ip_frag: handle MTU sizes not aligned to 8 bytes"). Briefly, the size of an ipv6 header is always 40 bytes. With an MTU of 1500, this will never produce a multiple of 8 bytes for the frag_size and this routine can never succeed. Since RTE_ASSERTS are disabled by default, this failure is typically ignored. To fix this, round down to the nearest 8 bytes and use this when producing the fragments. Fixes: 0aa31d7a5929 ("ip_frag: add IPv6 fragmentation support") Cc: stable@dpdk.org Signed-off-by: Chas Williams Acked-by: Luca Boccassi Acked-by: Konstantin Ananyev --- lib/librte_ip_frag/rte_ip_frag.h | 1 + lib/librte_ip_frag/rte_ipv6_fragmentation.c | 18 +++++++++++------- 2 files changed, 12 insertions(+), 7 deletions(-) diff --git a/lib/librte_ip_frag/rte_ip_frag.h b/lib/librte_ip_frag/rte_ip_frag.h index a4ccaf9d14..04fd9df528 100644 --- a/lib/librte_ip_frag/rte_ip_frag.h +++ b/lib/librte_ip_frag/rte_ip_frag.h @@ -115,6 +115,7 @@ struct rte_ip_frag_tbl { #define RTE_IPV6_EHDR_MF_MASK 1 #define RTE_IPV6_EHDR_FO_SHIFT 3 #define RTE_IPV6_EHDR_FO_MASK (~((1 << RTE_IPV6_EHDR_FO_SHIFT) - 1)) +#define RTE_IPV6_EHDR_FO_ALIGN (1 << RTE_IPV6_EHDR_FO_SHIFT) #define RTE_IPV6_FRAG_USED_MASK \ (RTE_IPV6_EHDR_MF_MASK | RTE_IPV6_EHDR_FO_MASK) diff --git a/lib/librte_ip_frag/rte_ipv6_fragmentation.c b/lib/librte_ip_frag/rte_ipv6_fragmentation.c index 62a7e4e830..b9437eb115 100644 --- a/lib/librte_ip_frag/rte_ipv6_fragmentation.c +++ b/lib/librte_ip_frag/rte_ipv6_fragmentation.c @@ -77,11 +77,14 @@ rte_ipv6_fragment_packet(struct rte_mbuf *pkt_in, uint32_t out_pkt_pos, in_seg_data_pos; uint32_t more_in_segs; uint16_t fragment_offset, frag_size; + uint64_t frag_bytes_remaining; - frag_size = (uint16_t)(mtu_size - sizeof(struct ipv6_hdr)); - - /* Fragment size should be a multiple of 8. */ - RTE_ASSERT((frag_size & ~RTE_IPV6_EHDR_FO_MASK) == 0); + /* + * Ensure the IP payload length of all fragments (except the + * the last fragment) are a multiple of 8 bytes per RFC2460. + */ + frag_size = RTE_ALIGN_FLOOR(mtu_size - sizeof(struct ipv6_hdr), + RTE_IPV6_EHDR_FO_ALIGN); /* Check that pkts_out is big enough to hold all fragments */ if (unlikely (frag_size * nb_pkts_out < @@ -111,6 +114,7 @@ rte_ipv6_fragment_packet(struct rte_mbuf *pkt_in, /* Reserve space for the IP header that will be built later */ out_pkt->data_len = sizeof(struct ipv6_hdr) + sizeof(struct ipv6_extension_fragment); out_pkt->pkt_len = sizeof(struct ipv6_hdr) + sizeof(struct ipv6_extension_fragment); + frag_bytes_remaining = frag_size; out_seg_prev = out_pkt; more_out_segs = 1; @@ -130,7 +134,7 @@ rte_ipv6_fragment_packet(struct rte_mbuf *pkt_in, /* Prepare indirect buffer */ rte_pktmbuf_attach(out_seg, in_seg); - len = mtu_size - out_pkt->pkt_len; + len = frag_bytes_remaining; if (len > (in_seg->data_len - in_seg_data_pos)) { len = in_seg->data_len - in_seg_data_pos; } @@ -140,11 +144,11 @@ rte_ipv6_fragment_packet(struct rte_mbuf *pkt_in, out_pkt->pkt_len); out_pkt->nb_segs += 1; in_seg_data_pos += len; + frag_bytes_remaining -= len; /* Current output packet (i.e. fragment) done ? */ - if (unlikely(out_pkt->pkt_len >= mtu_size)) { + if (unlikely(frag_bytes_remaining == 0)) more_out_segs = 0; - } /* Current input segment done ? */ if (unlikely(in_seg_data_pos == in_seg->data_len)) { -- 2.20.1